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Bielitzki R, Behrens M, Behrendt T, Franz A, Centner C, Hughes L, Patterson SD, Owens J, Behringer M, Schega L. The Discrepancy Between External and Internal Load/Intensity during Blood Flow Restriction Exercise: Understanding Blood Flow Restriction Pressure as Modulating Factor. SPORTS MEDICINE - OPEN 2024; 10:95. [PMID: 39227485 PMCID: PMC11371992 DOI: 10.1186/s40798-024-00759-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 07/29/2024] [Indexed: 09/05/2024]
Abstract
Physical exercise induces acute psychophysiological responses leading to chronic adaptations when the exercise stimulus is applied repeatedly, at sufficient time periods, and with appropriate magnitude. To maximize long-term training adaptations, it is crucial to control and manipulate the external load and the resulting psychophysiological strain. Therefore, scientists have developed a theoretical framework that distinguishes between the physical work performed during exercise (i.e., external load/intensity) and indicators of the body's psychophysiological response (i.e., internal load/intensity). However, the application of blood flow restriction (BFR) during exercise with low external loads/intensities (e.g., ≤ 30% of the one-repetition-maximum, ≤ 50% of maximum oxygen uptake) can induce physiological and perceptual responses, which are commonly associated with high external loads/intensities. This current opinion aimed to emphasize the mismatch between external and internal load/intensity when BFR is applied during exercise. In this regard, there is evidence that BFR can be used to manipulate both external load/intensity (by reducing total work when exercise is performed to exhaustion) and internal load/intensity (by leading to higher physiological and perceptual responses compared to exercise performed with the same external load/intensity without BFR). Furthermore, it is proposed to consider BFR as an additional exercise determinant, given that the amount of BFR pressure can determine not only the internal but also external load/intensity. Finally, terminological recommendations for the use of the proposed terms in the scientific context and for practitioners are given, which should be considered when designing, reporting, discussing, and presenting BFR studies, exercise, and/or training programs.
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Affiliation(s)
- Robert Bielitzki
- Department of Sport Science, Institute III, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
| | - Martin Behrens
- University of Applied Sciences for Sport and Management Potsdam, Potsdam, Germany
| | - Tom Behrendt
- Department of Sport Science, Institute III, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Alexander Franz
- Department of Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
| | - Christoph Centner
- Department of Sport and Science, University of Freiburg, Freiburg, Germany
| | - Luke Hughes
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK
| | - Stephen D Patterson
- Faculty of Sport, Technology and Health Science, St Mary's University, Twickenham, London, UK
| | - Johnny Owens
- Clinical Education Owens Recovery Science, San Antonio, TX, USA
| | - Michael Behringer
- Department of Sports Sciences, Goethe University Frankfurt, Frankfurt a. M., Germany
| | - Lutz Schega
- Department of Sport Science, Institute III, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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Lackner M, Grossmann F, Perret C, Flueck JL, Hertig-Godeschalk A. Chasing Gold: Heat Acclimation in Elite Handcyclists with Spinal Cord Injury. Int J Sports Med 2024; 45:733-738. [PMID: 38885662 DOI: 10.1055/a-2321-1832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Thermoregulation is impaired in individuals with a spinal cord lesion (SCI), affecting sweat capacity, heat loss, and core temperature. This can be particularly problematic for athletes with SCI who exercise in hot and humid conditions, like those during the Tokyo 2020 Paralympic Games. Heat acclimation can support optimal preparation for exercise in such challenging environments, but evidence is limited in endurance athletes with SCI. We evaluated whether seven consecutive days of exercise in the heat would result in heat acclimation. Five elite para-cycling athletes with SCI participated (two females, three males, median (Q1-Q3) 35 (31-51) years, four with paraplegia and one with tetraplegia). All tests and training sessions were performed in a heat chamber (30°C and 75% relative humidity). A time-to-exhaustion test was performed on day 1 (pretest) and day 7 (posttest). On days 2-6, athletes trained daily for one hour at 50-60% of individual peak power (PPeak). Comparing pretest and posttest, all athletes increased their body mass loss (p=0.04), sweat rate (p=0.04), and time to exhaustion (p=0.04). Effects varied between athletes for core temperature and heart rate. All athletes appeared to benefit from our heat acclimation protocol, helping to optimize their preparation for the Tokyo 2020 Paralympic Games.
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Affiliation(s)
- Mike Lackner
- Sports Therapy, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - Fabian Grossmann
- Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - Claudio Perret
- Neuro-Musculoskeletal Functioning and Mobility, Swiss Paraplegic Research, Nottwil, Switzerland
- Faculty of Health Sciences and Medicine, University of Lucerne, Luzern, Switzerland
| | - Joelle L Flueck
- Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
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Yu P, Fan Y, Wu H. Effects of Caffeine-Taurine Co-Ingestion on Endurance Cycling Performance in High Temperature and Humidity Environments. Sports Health 2024; 16:711-721. [PMID: 38406865 PMCID: PMC11346225 DOI: 10.1177/19417381241231627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024] Open
Abstract
BACKGROUND Taurine (TAU) and caffeine (CAF), as common ergogenic aids, are known to affect exercise performance; however, the effects of their combined supplementation, particularly in high temperature and humidity environments, have not been studied. HYPOTHESIS The combination of TAU and CAF will have a greater effect on endurance cycle performance and improve changes in physiological indicators during exercise compared with TAU or CAF supplementation alone and placebo. STUDY DESIGN Single-blind crossover randomized controlled study. LEVEL OF EVIDENCE Level 1. METHODS Twelve university students majoring in physical education volunteered to receive 4 different supplement ingestions: (1) placebo (maltodextrin), (2) TAU, (3) CAF, (4) TAU + CAF. After a 7-day washout period, participants completed a time to exhaustion (TTE) test in the heat (35°C, 65% relative humidity). RESULTS All experimental groups improved TTE compared with the placebo group. Peak and mean power of countermovement jump were significantly higher in the CAF group compared with the placebo group before the exhaustion exercise (P = 0.02, d = 1.2 and P = 0.04, d = 1.1, respectively). Blood lactate was significantly lower after the exhaustion test in the TAU group compared with the CAF (P < 0.01, d = 0.8) and TAU + CAF (P < 0.01, d = 0.7) groups. Core temperature in the TAU group was significantly reduced in the placebo group later in the exhaustion test (P < 0.01, d = 1.9). CONCLUSION In high temperature and humidity environments, acute TAU, CAF, and combined supplementation all improved TTE and did not affect recovery from lower limb neuromuscular fatigue compared with placebo, with TAU having the best effect. Combined supplementation failed to exhibit superimposed performance. CLINICAL RELEVANCE The results provide suggestions for the effects of TAU, CAF, and their combined intake on exercise performance in high temperature and humidity environments.
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Affiliation(s)
- Peiqi Yu
- Capital University of Physical Education and Sports, Beijing, China
- Comprehensive Key Laboratory of Sports Ability Evaluation and Research of the General Administration of Sport of China, Beijing, China
- Key Laboratory of Sports Function Assessment and Technical Analysis, Beijing, China
| | - Yongzhao Fan
- Department of Physical Education, Henan Normal University, Xinxiang, Henan, China
| | - Hao Wu
- Capital University of Physical Education and Sports, Beijing, China
- Comprehensive Key Laboratory of Sports Ability Evaluation and Research of the General Administration of Sport of China, Beijing, China
- Key Laboratory of Sports Function Assessment and Technical Analysis, Beijing, China
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4
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Wardenaar FC, Hoogervorst D, Ainsworth BE. Energy expenditure and physiological markers during a city mountain hike in the heat: A case study. Nutr Health 2024; 30:429-433. [PMID: 38676321 DOI: 10.1177/02601060241248315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Background: Energy expenditure may be difficult to assess when hiking difficult trails. Case presentation: We measured physical activity exercise energy expenditure (PAEE) directly from oxygen uptake using a mobile device (cardiopulmonary exercise testing, CPET), and by using a formula based on heart rate (HR), or metabolic equivalent values from the Compendium of Physical Activity, and other physiological outcomes. Outcomes and implications: Total PAEE (1342 kcal) using CPET showed a two-fold difference between ascending and descending (887 vs. 455 kcal) during a 124-min hike. For HR, PAEE was 1893kcal (+551 kcal overreporting), while compendium-based scenarios ranged from 1179 to 1446 kcal, which was in closer range (-163 to +104 kcal/min) compared to the CPET data. Fluid consumption was 1300 mL/hour, with 1.1% bodyweight loss, peak skin temperature of 35.2°C and core body temperature of 39.2°C. Recommendations: Tables reasonably predict energy expenditure while not precisely reflecting the actual situation.
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Affiliation(s)
| | | | - Barbara E Ainsworth
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
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Périard JD, Wilson MG, Tebeck ST, Stanley J, Girard O. Health status and heat preparation at a UCI World Tour multistage cycling race. J Sci Med Sport 2024:S1440-2440(24)00491-2. [PMID: 39242327 DOI: 10.1016/j.jsams.2024.08.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 08/14/2024] [Accepted: 08/20/2024] [Indexed: 09/09/2024]
Abstract
OBJECTIVES To assess health status and heat preparation of cyclists at the 2019 Tour Down Under and determine the alignment of heat mitigation strategies with current recommendations. DESIGN Cohort study. METHODS Twenty-three (17 % participation rate) male World Tour cyclists from five teams and 10 countries completed a pre-competition questionnaire evaluating exertional heat illness (EHI) history, pre-race health status, and heat mitigation and recovery strategies use. Associations between arrival days pre-competition, years as professional, nationality, team, history of EHI symptoms and diagnosis on heat mitigation and recovery strategy utilisation were assessed. RESULTS 65 % of cyclists reported previously experiencing one or more EHI symptom (cramping: 48 %) and 22 % a diagnosis of heat stroke. In the 10 days preceding the race, 26 % experienced one or more illness symptoms. 65 % trained in the heat (acclimatisation 8-25 days; acclimation: 3-7 days), which was associated with team (P = 0.047, ϕc = 0.61), nationality (P = 0.009, ϕc = 0.86) and EHI symptoms history (P = 0.058, ϕ = 0.43). All cyclists had a hydration plan, with links to team (0.5-1.0 L·h-1, P = 0.043, ϕc = 0.68) and EHI symptom history (1.0-1.5 L·h-1, P = 0.048, ϕ = 0.476). Most had pre-cooling (87 %) and mid-cooling (83 %) strategies, most commonly cold beverages (75 %) and neck collars (78 %), respectively. All cyclists planned on using at least one recovery strategy (massage: 87 %). CONCLUSIONS Our data indicate good alignment with current recommendations for competing in the heat, particularly for hydration, cooling and recovery strategies. Whilst the proportion of cyclists engaging in heat acclimation/acclimatisation is encouraging, greater awareness on adapting and implementing heat training is required.
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Affiliation(s)
- J D Périard
- Research Institute for Sport and Exercise, University of Canberra, Australia.
| | - M G Wilson
- Institute of Sport, Exercise and Health, University College London, UK; Aspetar Orthopaedic and Sports Medicine Hospital, Qatar
| | - S T Tebeck
- Department of Sports Science, South Australian Sports Institute of Sport, Australia; Alliance for Research in Exercise, Nutrition and Activity, University of South Australia, Australia
| | - J Stanley
- Department of Sports Science, South Australian Sports Institute of Sport, Australia; Alliance for Research in Exercise, Nutrition and Activity, University of South Australia, Australia; Australian Cycling Team, Auscycling, Gepps Cross, Australia
| | - O Girard
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Australia
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Segreti A, Celeski M, Guerra E, Crispino SP, Vespasiano F, Buzzelli L, Fossati C, Papalia R, Pigozzi F, Grigioni F. Effects of Environmental Conditions on Athlete's Cardiovascular System. J Clin Med 2024; 13:4961. [PMID: 39201103 PMCID: PMC11355938 DOI: 10.3390/jcm13164961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Revised: 08/13/2024] [Accepted: 08/17/2024] [Indexed: 09/02/2024] Open
Abstract
Environmental factors such as extreme temperatures, humidity, wind, pollution, altitude, and diving can significantly impact athletes' cardiovascular systems, potentially hindering their performance, particularly in outdoor sports. The urgency of this issue is heightened by the increasing prevalence of climate change and its associated conditions, including fluctuating pollution levels, temperature variations, and the spread of infectious diseases. Despite its critical importance, this topic is often overlooked in sports medicine. This narrative review seeks to address this gap by providing a comprehensive, evidence-based evaluation of how athletes respond to environmental stresses. A thorough assessment of current knowledge is essential to better prepare athletes for competition under environmental stress and to minimize the harmful effects of these factors. Specifically, adaptative strategies and preventative measures are vital to mitigating these environmental influences and ensuring athletes' safety.
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Affiliation(s)
- Andrea Segreti
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Roma, Italy; (C.F.); (F.P.)
| | - Mihail Celeski
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Emiliano Guerra
- Cardiology Division, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Policlinico di Modena, Via del Pozzo, 71, 41124 Modena, Italy;
| | - Simone Pasquale Crispino
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Francesca Vespasiano
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Lorenzo Buzzelli
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Chiara Fossati
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Roma, Italy; (C.F.); (F.P.)
| | - Rocco Papalia
- Department of Orthopaedic and Trauma Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy;
- Research Unit of Orthopaedic and Trauma Surgery, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy
| | - Fabio Pigozzi
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Roma, Italy; (C.F.); (F.P.)
| | - Francesco Grigioni
- Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy; (M.C.); (S.P.C.); (F.V.); (L.B.); (F.G.)
- Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy
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Nourmohammadi F, Gómez-Martín MB. Benefits of applying hourly resolution in the assessment of the climate aptitude to manage tourist activities in arid regions. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024; 68:1573-1585. [PMID: 38661946 PMCID: PMC11282155 DOI: 10.1007/s00484-024-02685-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/14/2024] [Accepted: 04/17/2024] [Indexed: 04/26/2024]
Abstract
The availability of reliable information on local climatic-tourism conditions is a growing need due to the influence it exerts on the quality of the organizational strategy of tourist destination's, and travel experience. Evaluations of the tourism potential of the climate have been carried out on a daily or monthly resolution, thus limiting the collection of detailed information that makes it possible to fine-tune tourism management and operational decision-making on an intraday scale. This research is the first case study to analyse the climatic suitability for nature tourism, using the weather types method at hourly resolution. The study applies to arid tourist destinations in Isfahan province (Iran). The detailed resolution has made it possible to identify the time slots favourable to the development of nature tourism in those periods of the year recognized as critical in the daily resolution analyses. In the same way, the hourly resolution has also identified critical bands in those periods indicated as favourable in the evaluations to daily resolution. The hourly resolution provides detailed information that can allow tourists and also tourism managers to establish intraday adaptation strategies that make it possible to develop the activity even in places with extreme climates.
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Affiliation(s)
- Fatemeh Nourmohammadi
- Department of Geography, University of Barcelona, Montalegre 6, Barcelona, 08001, Spain
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Ramos JAP, Ducker KJ, Riddell H, Landers G, Girard O, Brade CJ. Single Session Intermittent Heat Exposure With More Frequent and Shorter Cooling Breaks Facilitates Greater Training Intensity and Elicits Physiological Responses Comparable to Continuous Heat Exposure. Int J Sports Physiol Perform 2024; 19:798-808. [PMID: 38862102 DOI: 10.1123/ijspp.2023-0501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/03/2024] [Accepted: 04/18/2024] [Indexed: 06/13/2024]
Abstract
PURPOSE To investigate the influence of shorter, more frequent rest breaks with per-cooling as an alternative heat-acclimation session on physiological, perceptual, and self-paced maximal cycling performance, compared with continuous heat exposure. METHODS Thirteen participants completed 1 continuous and 3 intermittent-heat-exposure (IHE) maximal self-paced cycling protocols in a random order in heat (36 °C, 80% relative humidity): 1 × 60-minute exercise (CON), 3 × 20-minute exercise with 7.5-minute rest between sets (IHE-20), 4 × 15-minute exercise with 5-minute rest between sets (IHE-15), and 6 × 10-minute exercise with 3-minute rest between sets (IHE-10). Mixed-method per-cooling (crushed-ice ingestion and cooling vest) was applied during rest periods of all IHE protocols. RESULTS Total distance completed was greater in IHE-10, IHE-15, and IHE-20 than in CON (+11%, +9%, and +8%, respectively), with no difference observed between IHE protocols. Total time spent above 38.5 °C core temperature was longer in CON compared with IHE-15 and IHE-20 (+62% and +78%, respectively) but similar to IHE-10 (+5%). Furthermore, a longer time above 38.5 °C core temperature occurred in IHE-10 versus IHE-15 and IHE-20 (+54% and +69%, respectively). Sweat loss did not differ between conditions. CONCLUSION IHE with per-cooling may be a viable alternative heat-acclimation protocol in situations where training quality takes precedence over thermal stimulus or when both factors hold equal priority.
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Affiliation(s)
- Julian A P Ramos
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
| | - Kagan J Ducker
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
| | - Hugh Riddell
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
| | - Grant Landers
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, WA, Australia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, WA, Australia
| | - Carly J Brade
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
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Bauman J, Spano S, Storkan M. Heat-Related Illnesses. Emerg Med Clin North Am 2024; 42:485-492. [PMID: 38925769 DOI: 10.1016/j.emc.2024.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
There is a growing incidence of heat-related illnesses due to rising global temperatures. Heat-related illnesses range from mild to severe, with heat stroke being the most critical. The wet bulb global temperature index considers humidity and solar intensity; its use is recommended to estimate heat stress on an individual and mitigate risk. Efficient cooling methods, such as cold water immersion, are essential in severe cases. Prevention is through hydration, appropriate clothing, recognition of high risk medications, and awareness of environmental conditions. Recognizing heat-related illnesses early in the clinical course and implementing rapid cooling strategies reduces morbidity and mortality.
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Affiliation(s)
- Jonathan Bauman
- Department of Emergency Medicine, University of California San Francisco, 155 N. Fresno Street, Fresno, CA 93701, USA
| | - Susanne Spano
- Department of Emergency Medicine, University of California San Francisco, 155 N. Fresno Street, Fresno, CA 93701, USA.
| | - Michelle Storkan
- Department of Emergency Medicine, University of California San Francisco, 155 N. Fresno Street, Fresno, CA 93701, USA
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Comp G, Ferrari A, Seigneur S. Desert Medicine. Emerg Med Clin North Am 2024; 42:565-580. [PMID: 38925775 DOI: 10.1016/j.emc.2024.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Deserts are defined by their arid nature, characterized by little rainfall, and often featuring vast stretches of sandy terrain with sparse vegetation. The resulting variations in temperature, humidity, and topography predispose patients to medical conditions that practitioners in both rural and urban deserts must recognize and manage. This article will equip medical practitioners with the essential knowledge and tools to navigate these complexities, including a description of specific environmental considerations and challenges encountered while providing care in these desert locations, common conditions associated with extreme heat and solar radiation, and animal encounters.
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Affiliation(s)
- Geoffrey Comp
- Valleywise Health Medical Center; University of Arizona College of Medicine-Phoenix; Creighton University School of Medicine-Phoenix.
| | | | - Savannah Seigneur
- Valleywise Health Medical Center; Creighton University School of Medicine-Phoenix
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John K, Page J, Heffernan SM, Conway GE, Bezodis NE, Kilduff LP, Clark B, Périard JD, Waldron M. The effect of a 4-week, remotely administered, post-exercise passive leg heating intervention on determinants of endurance performance. Eur J Appl Physiol 2024:10.1007/s00421-024-05558-4. [PMID: 39052044 DOI: 10.1007/s00421-024-05558-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 07/13/2024] [Indexed: 07/27/2024]
Abstract
PURPOSE Post-exercise passive heating has been reported to augment adaptations associated with endurance training. The current study evaluated the effect of a 4-week remotely administered, post-exercise passive leg heating protocol, using an electrically heated layering ensemble, on determinants of endurance performance. METHODS Thirty recreationally trained participants were randomly allocated to either a post-exercise passive leg heating (PAH, n = 16) or unsupervised training only control group (CON, n = 14). The PAH group wore the passive heating ensemble for 90-120 min/day, completing a total of 20 (16 post-exercise and 4 stand-alone leg heating) sessions across 4 weeks. Whole-body (peak oxygen uptake, gas exchange threshold, gross efficiency and pulmonary oxygen uptake kinetics), single-leg exercise (critical torque and NIRS-derived muscle oxygenation), resting vascular characteristics (flow-mediated dilation) and angiogenic blood measures (nitrate, vascular endothelial growth factor and hypoxia inducible factor 1-α) were recorded to characterize the endurance phenotype. All measures were assessed before (PRE), at 2 weeks (MID) and after (POST) the intervention. RESULTS There was no effect of the intervention on test of whole-body endurance capacity, vascular function or blood markers (p > 0.05). However, oxygen kinetics were adversely affected by PAH, denoted by a slowing of the phase II time constant; τ (p = 0.02). Furthermore, critical torque-deoxygenation ratio was improved in CON relative to PAH (p = 0.03). CONCLUSION We have demonstrated that PAH had no ergogenic benefit but instead elicited some unfavourable effects on sub-maximal exercise characteristics in recreationally trained individuals.
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Affiliation(s)
- Kevin John
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK
| | - Joe Page
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK
| | - Shane M Heffernan
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK
| | - Gillian E Conway
- Institute of Life Science, Faculty of Medicine, Health and Life Sciences, Swansea University, Swansea, UK
| | - Neil E Bezodis
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
| | - Liam P Kilduff
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
| | - Brad Clark
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
| | - Mark Waldron
- Applied Sports Science Technology and Medicine (A-STEM) Research Centre, Faculty of Science & Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, Wales, UK.
- Welsh Institute of Performance Science, Swansea University, Swansea, UK.
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Maroochydore, QLD, Australia.
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Navas-Martín MÁ, Cuerdo-Vilches T, López-Bueno JA, Díaz J, Linares C, Sánchez-Martínez G. Human adaptation to heat in the context of climate change: A conceptual framework. ENVIRONMENTAL RESEARCH 2024; 252:118803. [PMID: 38565417 DOI: 10.1016/j.envres.2024.118803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/04/2024]
Abstract
Climate change is causing serious damage to natural and social systems, as well as having an impact on human health. Among the direct effects of climate change is the rise in global surface temperatures and the increase in the frequency, duration, intensity and severity of heat waves. In addition, understanding of the adaptation process of the exposed population remains limited, posing a challenge in accurately estimating heat-related morbidity and mortality. In this context, this study seeks to establish a conceptual framework that would make it easier to understand and organise knowledge about human adaptation to heat and the factors that may influence this process. An inductive approach based on grounded theory was used, through the analysis of case studies connecting concepts. The proposed conceptual framework is made up of five components (climate change, vulnerability, health risks of heat, axes of inequality and health outcomes), three heat-adaptation domains (physiological, cultural and political), two levels (individual and social), and the pre-existing before a heat event. The application of this conceptual framework facilitates the assistance of decision-makers in planning and implementing effective adaptation measures. Recognizing the importance of addressing heat adaptation as a health problem that calls for political solutions and social changes. Accordingly, this requires a multidisciplinary approach that would foster the participation and collaboration of multiple actors for the purpose of proposing effective measures to address the health impact of the rise in temperature.
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Affiliation(s)
- Miguel Ángel Navas-Martín
- Programme in Biomedical Sciences and Public Health, National University of Distance Education (UNED), Madrid, Spain; National School of Public Health, Carlos III Institute of Health (ISCIII), Madrid, Spain.
| | - Teresa Cuerdo-Vilches
- Eduardo Torroja Construction Sciences Institute (IETCC), Spanish National Research Council (CSIC), Madrid, Spain
| | | | - Julio Díaz
- National School of Public Health, Carlos III Institute of Health (ISCIII), Madrid, Spain
| | - Cristina Linares
- National School of Public Health, Carlos III Institute of Health (ISCIII), Madrid, Spain
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13
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Liu T. The roles of ACE I/D and ACTN3 R577X gene variants in heat acclimation. Heliyon 2024; 10:e33172. [PMID: 38984309 PMCID: PMC11231590 DOI: 10.1016/j.heliyon.2024.e33172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/28/2024] [Accepted: 06/14/2024] [Indexed: 07/11/2024] Open
Abstract
Roles of genes in heat acclimation (HA, repeated exercise-heat exposures) had not been explored. ACE I/D and ACTN3 R577X genetic polymorphisms are closely associated with outstanding exercise performances. This study investigated whether the two polymorphisms influenced the response to HA. Fifty young Han nationality male subjects were selected and conducted HA for 2 weeks. Exercise indicators (5-km run, push-up and 100-m run) were tested and rest aural thermometry (RTau) was measured before and after HA. ACE gene was grouped by I homozygote and D carrier, and ACTN3 gene was grouped by R homozygote and X carrier. Results showed that there were no differences between groups in age, body mass index, exercise indicators and RTau before HA. After HA, RTau of ACE I homozygote was lower than that of D carrier [F (1, 48) = 9.12, p = 0.004, η = 0.40]. Compared with RTau before HA, that of I homozygote decreased after HA (Δ = -0.26 °C, 95 % CI -0.34-0.18, p < 0.001), while that of D carrier did not change. There was a ACE gene × HA interaction in RTau [F (1, 48) = 14.26, p < 0.001, η = 0.48]. No effect of ACTN3 gene on RTau was observed. For exercise indicators, there were no differences between groups after HA, and no gene × HA interactions were observed. There may be a strong interaction of ACE gene and HA in the change of rest core temperature. I homozygote may have an advantage on improving heat tolerance.
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Affiliation(s)
- Tao Liu
- Special Operations Experiment Center, Chinese People's Liberation Army Special Warfare School, Guangzhou, Guangdong, China
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14
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Flunker JC, Spector JT, Blancas M, Briggs NL, Flores M, Whitaker CR, Schoonover T, Cardoso T. Farmworker-Relevant Heat Exposure in Different Crop and Shade Conditions. J Agromedicine 2024:1-14. [PMID: 38874305 DOI: 10.1080/1059924x.2024.2365647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
OBJECTIVES Agricultural workers are at risk of heat-related illness, which is preventable. Few field studies have compared farmworker-relevant heat exposure in different conditions. We examined heat exposure over time in different potential shade and work locations to inform future occupational heat prevention approaches. METHODS We assessed heat exposure in Eastern Washington State (WA) cherry and grape fields in August 2022. QUESTemp° monitors recorded Wet Bulb Globe Temperature (WBGT) and Black Globe Temperature (BGT) every 10 min from approximately 07:00-14:00 for three days in the center of crop rows (mid-row), under portable shade structures (shade), and in open field (open) locations. Linear mixed effects regression (LMER) models compared WBGT and BGT among field locations. Hourly time-weighted average WBGT and comparisons with occupational exposure limits (OELs) were computed for different hypothetical work-rest cycles during the hottest sampling hours, assuming different worker effort levels, rest locations (mid-row versus shade), and acclimatization statuses. RESULTS Across all crops and locations during the study period, the mean/SD air temperature was 31°C (88°F)/3.9°C (6.9°F), with a maximum temperature of 39°C (102°F) and a mean/SD relative humidity of 30%/9.6%. LMER models suggested no significant difference in mid-row versus open WBGT but significantly lower WBGT in shade versus open locations for both cherries (main effect -5.14: 95% confidence interval [CI] -6.97,-3.32) and grapes (-6.20: 95%CI -7.73,-4.67), though this difference diminished over the course of the day. BGT was significantly higher in the mid-row than the shade (cherries main effect 14.33: 95%CI 9.52,19.13 and grapes 17.10: 95%CI 13.44,20.75). During the hottest sampling hour, the exceedances of OELs were reduced with assumptions of increased shaded break lengths, reduced effort level, and acclimatization. CONCLUSIONS Shade canopies, but not the crops studied, provided significant reductions in heat exposure. We observed increased protection from heat assuming longer shaded breaks and reduced effort levels. Results highlight the need for additional field research on the effectiveness, feasibility, and acceptability of different shade types and work-rest cycles to guide employer optimization of best practices for worker protections, including acclimatization before high heat, sufficient shaded rest time, reduced effort levels as the day warms, and avoiding work in peak heat.
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Affiliation(s)
- John C Flunker
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - June T Spector
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
- Department of Labor and Industries, Safety & Health Assessment and Research for Prevention (SHARP) Program, Tumwater, WA, USA
| | - Maria Blancas
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Nicole L Briggs
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Miriam Flores
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Carolyn Reeb- Whitaker
- Department of Labor and Industries, Safety & Health Assessment and Research for Prevention (SHARP) Program, Tumwater, WA, USA
| | - Todd Schoonover
- Department of Labor and Industries, Safety & Health Assessment and Research for Prevention (SHARP) Program, Tumwater, WA, USA
| | - Tamre Cardoso
- Department of Statistics, University of Washington, Seattle, WA, USA
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15
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Havenga H, Gharbi D, Sewry N, Language B, Neumann FH, Finch JM, Hill T, Boulter J, Jordaan E, Piketh SJ, Schwellnus M, Burger RP. Healthy environments for athleTes (HEAT): environmental conditions along a 90 km ultra-marathon event, South Africa. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024:10.1007/s00484-024-02703-8. [PMID: 38869702 DOI: 10.1007/s00484-024-02703-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 04/22/2024] [Accepted: 05/09/2024] [Indexed: 06/14/2024]
Abstract
This paper provides an overview of the HEAT (Healthy Environments for AthleTes) project, which aims to understand the impact of environmental conditions on athlete health and performance during major sporting events such as long-distance running, cycling, and triathlons. In collaboration with the SAFER (Strategies to reduce Adverse medical events For the ExerciseR) initiative, the HEAT project carried out a field campaign at the 2022 Comrades Marathon in the KwaZulu-Natal province of South Africa. The measurement campaign deployed seven weather stations, seven PM2.5 monitors and one spore trap along the 90 km route to capture spatially representative measurements of complex micro-climates, allergenic aerospora, and particulate matter exposure. The results indicate that runners were exposed to moderate risk heat stress conditions. Novel findings from this initial campaign shows elevated and potentially harmful PM2.5 levels at spectator areas, possibly coinciding with small fire events around the race day festivities. Our findings show values PM2.5 levels over the WHO 24-h guidelines at all stations, while 2000 µg/m3 at two stations. However, the lack of an acute exposure standard means direct health impacts cannot be quantified in the context of a sport event. The HEAT project highlights important aspects of race day monitoring; regional scale climatology has an impact on the race day conditions, the microclimatic conditions (pollution and meteorology) are not necessarily captured by proximity instruments and direct environmental measurements are required to accurately capture conditions along the route.
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Affiliation(s)
- H Havenga
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
| | - D Gharbi
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - N Sewry
- Sport, Exercise Medicine and Lifestyle Institute (SEMLI), Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- International Olympic Committee Research Centre, Pretoria, South Africa
| | - B Language
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - F H Neumann
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - J M Finch
- School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - T Hill
- School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - J Boulter
- Comrades Marathon Association (CMA), Medical Director, Pietermaritzburg, South Africa
| | - E Jordaan
- Biostatistics Unit, South African Medical Research Council, Cape Town, South Africa
- Statistics and Population Studies Department, University of the Western Cape, Cape Town, Western Cape, South Africa
| | - S J Piketh
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - M Schwellnus
- Sport, Exercise Medicine and Lifestyle Institute (SEMLI), Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- International Olympic Committee Research Centre, Pretoria, South Africa
| | - R P Burger
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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16
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Bennett S, Tiollier E, Owens DJ, Brocherie F, Louis JB. Implications of Heat Stress-induced Metabolic Alterations for Endurance Training. Int J Sports Med 2024; 45:422-435. [PMID: 38401534 DOI: 10.1055/a-2251-3170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2024]
Abstract
Inducing a heat-acclimated phenotype via repeated heat stress improves exercise capacity and reduces athletes̓ risk of hyperthermia and heat illness. Given the increased number of international sporting events hosted in countries with warmer climates, heat acclimation strategies are increasingly popular among endurance athletes to optimize performance in hot environments. At the tissue level, completing endurance exercise under heat stress may augment endurance training adaptation, including mitochondrial and cardiovascular remodeling due to increased perturbations to cellular homeostasis as a consequence of metabolic and cardiovascular load, and this may improve endurance training adaptation and subsequent performance. This review provides an up-to-date overview of the metabolic impact of heat stress during endurance exercise, including proposed underlying mechanisms of altered substrate utilization. Against this metabolic backdrop, the current literature highlighting the role of heat stress in augmenting training adaptation and subsequent endurance performance will be presented with practical implications and opportunities for future research.
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Affiliation(s)
- Samuel Bennett
- Center for Biological Clocks Research, Texas A&M University, College Station, United States
| | - Eve Tiollier
- Laboratory Sport, Expertise and Performance, Research Department, Institut National du Sport de l'Expertise et de la Performance, Paris, France
| | - Daniel J Owens
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom of Great Britain and Northern Ireland
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance, Research Department, Institut National du Sport de l'Expertise et de la Performance, Paris, France
| | - Julien B Louis
- Laboratory Sport, Expertise and Performance, Research Department, Institut National du Sport de l'Expertise et de la Performance, Paris, France
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom of Great Britain and Northern Ireland
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17
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Tan SCC, Tran TCK, Chiang CYN, Pan J, Low ICC. External auricle temperature enhances ear-based wearable accuracy during physiological strain monitoring in the heat. Sci Rep 2024; 14:12418. [PMID: 38816453 PMCID: PMC11139936 DOI: 10.1038/s41598-024-63241-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024] Open
Abstract
Body core temperature (Tc) monitoring is crucial for minimizing heat injury risk. However, validated strategies are invasive and expensive. Although promising, aural canal temperature (Tac) is susceptible to environmental influences. This study investigated whether incorporation of external auricle temperature (Tea) into an ear-based Tc algorithm enhances its accuracy during multiple heat stress conditions. Twenty males (mean ± SD; age = 25 ± 3 years, BMI = 21.7 ± 1.8, body fat = 12 ± 3%, maximal aerobic capacity (VO2max) = 64 ± 7 ml/kg/min) donned an ear-based wearable and performed a passive heating (PAH), running (RUN) and brisk walking trial (WALK). PAH comprised of immersion in hot water (42.0 ± 0.3 °C). RUN (70 ± 3%VO2max) and WALK (50 ± 10%VO2max) were conducted in an environmental chamber (Tdb = 30.0 ± 0.2 °C, RH = 71 ± 2%). Several Tc models, developed using Tac, Tea and heart rate, were validated against gastrointestinal temperature. Inclusion of Tea as a model input improved the accuracy of the ear-based Tc algorithm. Our best performing model (Trf3) displayed good group prediction errors (mean bias error = - 0.02 ± 0.26 °C) but exhibited individual prediction errors (percentage target attainment ± 0.40 °C = 88%) that marginally exceeded our validity criterion. Therefore, Trf3 demonstrates potential utility for group-based Tc monitoring, with additional refinement needed to extend its applicability to personalized heat strain monitoring.
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Affiliation(s)
- Shawn Chee Chong Tan
- Human Potential Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD9, 2 Medical Drive Level 4, Singapore, 117593, Singapore
| | - Trinh Canh Khanh Tran
- Human Potential Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD9, 2 Medical Drive Level 4, Singapore, 117593, Singapore
| | - Charis Yi Ning Chiang
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Jieming Pan
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Ivan Cherh Chiet Low
- Human Potential Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD9, 2 Medical Drive Level 4, Singapore, 117593, Singapore.
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18
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Dunn RA, Fry LA, Sekiguchi Y, Benjamin CL, Manning CN, Huggins RA, Stearns RL, Casa DJ. Effect of Heat Acclimatization, Heat Acclimation, and Intermittent Heat Training on Maximal Oxygen Uptake. Sports Health 2024:19417381241249470. [PMID: 38708678 DOI: 10.1177/19417381241249470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024] Open
Abstract
BACKGROUND Maximal oxygen uptake (VO2max) is an important determinant of endurance performance. Heat acclimation/acclimatization (HA/HAz) elicits improvements in endurance performance. Upon heat exposure reduction, intermittent heat training (IHT) may alleviate HA/HAz adaptation decay; however, corresponding VO2max responses are unknown. HYPOTHESIS VO2max is maintained after HAz/HA; IHT mitigates decrements in aerobic power after HAz/HA. STUDY DESIGN Interventional study. LEVEL OF EVIDENCE Level 3. METHODS A total of 27 male endurance runners (mean ± SD; age, 36 ± 12 years; body mass, 73.03 ± 8.97 kg; height, 178.81 ± 6.39 cm) completed VO2max testing at 5 timepoints; baseline, post-HAz, post-HA, and weeks 4 and 8 of IHT (IHT4, IHT8). After baseline testing, participants completed HAz, preceded by 5 days of HA involving exercise to induce hyperthermia for 60 minutes in the heat (ambient temperature, 39.13 ± 1.37°C; relative humidity, 51.08 ± 8.42%). Participants were assigned randomly to 1 of 3 IHT groups: once-weekly, twice-weekly, or no IHT. Differences in VO2max, velocity at VO2max (vVO2), and maximal heart rate (HRmax) at all 5 timepoints were analyzed using repeated-measure analyses of variance with Bonferroni corrections post hoc. RESULTS No significant VO2max or vVO2 differences were observed between baseline, post-HAz, or post-HA (P = 0.36 and P = 0.09, respectively). No significant group or time effects were identified for VO2max or vVO2 at post-HA, IHT4, and IHT8 (P = 0.67 and P = 0.21, respectively). Significant HRmax differences were observed between baseline and post-HA tests (P < 0.01). No significant group or time HRmax differences shown for post-HA, IHT4, and IHT8 (P = 0.59). CONCLUSION VO2max was not reduced among endurance runners after HA/HAz and IHT potentially due to participants' similar aerobic training status and high aerobic fitness levels. CLINICAL RELEVANCE HAz/HA and IHT maintain aerobic power in endurance runners, with HAz/HA procuring reductions in HRmax.
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Affiliation(s)
- Ryan A Dunn
- Sports Performance Laboratory, Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, Texas
| | - Lauren A Fry
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Yasuki Sekiguchi
- Sports Performance Laboratory, Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, Texas and Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Courteney L Benjamin
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut and Department of Kinesiology, Samford University, Birmingham, Alabama
| | - Ciara N Manning
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Robert A Huggins
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
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Brown HA, Topham TH, Clark B, Woodward AP, Ioannou LG, Flouris AD, Telford RD, Smallcombe JW, Jay O, Périard JD. Thermal and cardiovascular heat adaptations in active adolescents following summer. Temperature (Austin) 2024; 11:254-265. [PMID: 39193050 PMCID: PMC11346565 DOI: 10.1080/23328940.2024.2347161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/09/2024] [Accepted: 04/19/2024] [Indexed: 08/29/2024] Open
Abstract
This study aimed to investigate seasonal heat acclimatization in active adolescents following summer. Fifteen (5 females) active adolescents (14.6 ± 1.0 y) completed a 45-min heat response test (HRT) walking at 60% V ˙ O2peak in 40°C and 30% relative humidity before and after summer (i.e. November 2022 and March 2023). During the HRT, gastro-intestinal temperature (Tgi), skin temperature (Tsk), heart rate, local sweat rate (LSR) and whole-body sweat loss (WBSL) were recorded. Carbon monoxide rebreathing and dual-energy X-ray absorptiometry scans determined resting hematological measures and body composition. Participants completed physical activity (PA) diaries and wore an accelerometer for two one-week periods (pre- and post-summer). Daytime wet-bulb globe temperature (WBGT) was calculated for each summer day. Data are presented as posterior mean and 90% credible intervals. Participants reported 7 ± 4 h·wk-1 of outdoor PA, and daytime WBGT was 21.2 ± 4.6°C. Following summer, resting Tgi and heart rate were reduced by 0.2°C [-0.3, -0.1; probability of direction = 99%] and 7 beats·min-1 [-10, -3; 100%], respectively. During the HRT, there was an earlier onset of sweating (-0.2°C [-0.3, -0.0; 98%]), an attenuated rise of Tgi (0.2°C [-0.5, 0.0; 92%]) and mean Tsk changed by -0.2°C [-0.5, 0.1; 86%]. There was minimal evidence for heat adaptations in LSR or WBSL, hematological parameters or perceptual measures. This is the first study to demonstrate seasonal heat adaptations in active adolescents. Reductions in resting Tgi and exercising Tsk and a lower Tgi at the onset of sweating were associated with a smaller rise in Tgi during the HRT following summer.
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Affiliation(s)
- Harry A. Brown
- Research Institute for Sport and Exercise Science (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Thomas H. Topham
- Research Institute for Sport and Exercise Science (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Brad Clark
- Research Institute for Sport and Exercise Science (UCRISE), University of Canberra, Bruce, ACT, Australia
| | | | - Leonidas G. Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Andreas D. Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Richard D. Telford
- Research Institute for Sport and Exercise Science (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - James W. Smallcombe
- Heat and Health Research Incubator, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Ollie Jay
- Heat and Health Research Incubator, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Julien D. Périard
- Research Institute for Sport and Exercise Science (UCRISE), University of Canberra, Bruce, ACT, Australia
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20
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Ebisuda Y, Mukai K, Takahashi Y, Yoshida T, Matsuhashi T, Kawano A, Miyata H, Kuwahara M, Ohmura H. Heat acclimation improves exercise performance in hot conditions and increases heat shock protein 70 and 90 of skeletal muscles in Thoroughbred horses. Physiol Rep 2024; 12:e16083. [PMID: 38789393 PMCID: PMC11126422 DOI: 10.14814/phy2.16083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/09/2024] [Accepted: 05/12/2024] [Indexed: 05/26/2024] Open
Abstract
This study aimed to determine whether heat acclimation could induce adaptations in exercise performance, thermoregulation, and the expression of proteins associated with heat stress in the skeletal muscles of Thoroughbreds. Thirteen trained Thoroughbreds performed 3 weeks of training protocols, consisting of cantering at 90% maximal oxygen consumption (VO2max) for 2 min 2 days/week and cantering at 7 m/s for 3 min 1 day/week, followed by a 20-min walk in either a control group (CON; Wet Bulb Globe Temperature [WBGT] 12-13°C; n = 6) or a heat acclimation group (HA; WBGT 29-30°C; n = 7). Before and after heat acclimation, standardized exercise tests (SET) were conducted, cantering at 7 m/s for 90 s and at 115% VO2max until fatigue in hot conditions. Increases in run time (p = 0.0301), peak cardiac output (p = 0.0248), and peak stroke volume (p = 0.0113) were greater in HA than in CON. Pulmonary artery temperature at 7 m/s was lower in HA than in CON (p = 0.0332). The expression of heat shock protein 70 (p = 0.0201) and 90 (p = 0.0167) increased in HA, but not in CON. These results suggest that heat acclimation elicits improvements in exercise performance and thermoregulation under hot conditions, with a protective adaptation to heat stress in equine skeletal muscles.
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Affiliation(s)
- Yusaku Ebisuda
- Sports Science DivisionEquine Research Institute, Japan Racing AssociationShimotsukeJapan
| | - Kazutaka Mukai
- Sports Science DivisionEquine Research Institute, Japan Racing AssociationShimotsukeJapan
| | - Yuji Takahashi
- Sports Science DivisionEquine Research Institute, Japan Racing AssociationShimotsukeJapan
| | - Toshinobu Yoshida
- Sports Science DivisionEquine Research Institute, Japan Racing AssociationShimotsukeJapan
| | - Tsubasa Matsuhashi
- Department of Biological Sciences, Graduate School of Sciences and Technology for InnovationYamaguchi UniversityYamaguchiJapan
| | - Aoto Kawano
- Department of Biological Sciences, Graduate School of Sciences and Technology for InnovationYamaguchi UniversityYamaguchiJapan
| | - Hirofumi Miyata
- Department of Biological Sciences, Graduate School of Sciences and Technology for InnovationYamaguchi UniversityYamaguchiJapan
| | - Masayoshi Kuwahara
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Hajime Ohmura
- Sports Science DivisionEquine Research Institute, Japan Racing AssociationShimotsukeJapan
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21
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Zarębska EA, Kusy K, Korman P, Słomińska EM, Zieliński J. Exercise-induced changes in lower limbs skin temperature against plasma ATP among individuals with various type and level of physical activity. J Therm Biol 2024; 122:103877. [PMID: 38850622 DOI: 10.1016/j.jtherbio.2024.103877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024]
Abstract
The objective of the study was to examine the lower limbs skin temperature (TSK) changes in response to exhaustive whole-body exercise in trained individuals in reference to changes in plasma adenosine triphosphate (ATP). Eighteen trained participants from distinct sport type ‒ endurance (25.2 ± 4.9 yr) and speed-power (25.8 ± 3.1 yr), and 9 controls (24,9 ± 4,3 yr) ‒ were examined. Lower limbs TSK and plasma ATP measures were applied in parallel in response to incremental treadmill test and during 30-min recovery period. Plasma ATP kinetics were inversely associated to changes in TSK. The first significant decrease in TSK (76-89% of V˙ O2MAX) occurred shortly before a significant plasma ATP increase (86-97% of V˙ O2MAX). During recovery, TSK increased, reaching pre-exercise values (before exercise vs. after 30-min recovery: 31.6 ± 0.4 °C vs. 32.0 ± 0.8 °C, p = 0.855 in endurance; 32.4 ± 0.5 °C vs. 32.9 ± 0.5 °C, p = 0.061 in speed-power; 31.9 ± 0.7 °C vs. 32.4 ± 0.8 °C, p = 0.222 in controls). Plasma ATP concentration did not returned to pre-exercise values in well trained participants (before exercise vs. after 30-min recovery: 699 ± 57 nmol l-1 vs. 854 ± 31 nmol l-1, p < 0.001, η2 = 0.961 and 812 ± 35 nmol l-1 vs. 975 ± 55 nmol l-1, p < 0.001, η2 = 0.974 in endurance and speed-power, respectively), unlike in controls (651 ± 40 nmol l-1 vs. 687 ± 61 nmol·l-1, p = 0.58, η2 = 0.918). The magnitude of TSK and plasma ATP response differed between the groups (p < 0.001, η2 = 0.410 for TSK; p < 0.001, η2 = 0.833 for plasma ATP). We conclude that lower limbs TSK change indirectly corresponds to the reverse course of plasma ATP during incremental exercise and the magnitude of the response depends on the level of physical activity and the associated to it long-term metabolic adaptation.
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Affiliation(s)
- Ewa A Zarębska
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Krzysztof Kusy
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Paweł Korman
- Department of Physical Therapy and Sports Recovery, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Ewa M Słomińska
- Department of Biochemistry, Medical University of Gdansk, 80-211, Gdansk, Poland.
| | - Jacek Zieliński
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
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Moyen NE, Ediger TR, Taylor KM, Hancock EG, Holden LD, Tracy EE, Kay PH, Irick CR, Kotzen KJ, He DD. Sleeping for One Week on a Temperature-Controlled Mattress Cover Improves Sleep and Cardiovascular Recovery. Bioengineering (Basel) 2024; 11:352. [PMID: 38671774 PMCID: PMC11048088 DOI: 10.3390/bioengineering11040352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/19/2024] [Accepted: 03/31/2024] [Indexed: 04/28/2024] Open
Abstract
Body temperature should be tightly regulated for optimal sleep. However, various extrinsic and intrinsic factors can alter body temperature during sleep. In a free-living study, we examined how sleep and cardiovascular health metrics were affected by sleeping for one week with (Pod ON) vs. without (Pod OFF), an active temperature-controlled mattress cover (the Eight Sleep Pod). A total of 54 subjects wore a home sleep test device (HST) for eight nights: four nights each with Pod ON and OFF (>300 total HST nights). Nightly sleeping heart rate (HR) and heart rate variability (HRV) were collected. Compared to Pod OFF, men and women sleeping at cooler temperatures in the first half of the night significantly improved deep (+14 min; +22% mean change; p = 0.003) and REM (+9 min; +25% mean change; p = 0.033) sleep, respectively. Men sleeping at warm temperatures in the second half of the night significantly improved light sleep (+23 min; +19% mean change; p = 0.023). Overall, sleeping HR (-2% mean change) and HRV (+7% mean change) significantly improved with Pod ON (p < 0.01). To our knowledge, this is the first study to show a continuously temperature-regulated bed surface can (1) significantly modify time spent in specific sleep stages in certain parts of the night, and (2) enhance cardiovascular recovery during sleep.
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Brown HA, Topham TH, Clark B, Ioannou LG, Flouris AD, Smallcombe JW, Telford RD, Jay O, Périard JD. Quantifying Exercise Heat Acclimatisation in Athletes and Military Personnel: A Systematic Review and Meta-analysis. Sports Med 2024; 54:727-741. [PMID: 38051495 DOI: 10.1007/s40279-023-01972-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2023] [Indexed: 12/07/2023]
Abstract
BACKGROUND Athletes and military personnel are often expected to compete and work in hot and/or humid environments, where decrements in performance and an increased risk of exertional heat illness are prevalent. A physiological strategy for reducing the adverse effects of heat stress is to acclimatise to the heat. OBJECTIVE The aim of this systematic review was to quantify the effects of relocating to a hotter climate to undergo heat acclimatisation in athletes and military personnel. ELIGIBILITY CRITERIA Studies investigating the effects of heat acclimatisation in non-acclimatised athletes and military personnel via relocation to a hot climate for < 6 weeks were included. DATA SOURCES MEDLINE, SPORTDiscus, CINAHL Plus with Full Text and Scopus were searched from inception to June 2022. RISK OF BIAS A modified version of the McMaster critical review form was utilised independently by two authors to assess the risk of bias. DATA SYNTHESIS A Bayesian multi-level meta-analysis was conducted on five outcome measures, including resting core temperature and heart rate, the change in core temperature and heart rate during a heat response test and sweat rate. Wet-bulb globe temperature (WBGT), daily training duration and protocol length were used as predictor variables. Along with posterior means and 90% credible intervals (CrI), the probability of direction (Pd) was calculated. RESULTS Eighteen articles from twelve independent studies were included. Fourteen articles (nine studies) provided data for the meta-analyses. Whilst accounting for WBGT, daily training duration and protocol length, population estimates indicated a reduction in resting core temperature and heart rate of - 0.19 °C [90% CrI: - 0.41 to 0.05, Pd = 91%] and - 6 beats·min-1 [90% CrI: - 16 to 5, Pd = 83%], respectively. Furthermore, the rise in core temperature and heart rate during a heat response test were attenuated by - 0.24 °C [90% CrI: - 0.67 to 0.20, Pd = 85%] and - 7 beats·min-1 [90% CrI: - 18 to 4, Pd = 87%]. Changes in sweat rate were conflicting (0.01 L·h-1 [90% CrI: - 0.38 to 0.40, Pd = 53%]), primarily due to two studies demonstrating a reduction in sweat rate following heat acclimatisation. CONCLUSIONS Data from athletes and military personnel relocating to a hotter climate were consistent with a reduction in resting core temperature and heart rate, in addition to an attenuated rise in core temperature and heart rate during an exercise-based heat response test. An increase in sweat rate is also attainable, with the extent of these adaptations dependent on WBGT, daily training duration and protocol length. PROSPERO REGISTRATION CRD42022337761.
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Affiliation(s)
- Harry A Brown
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Thomas H Topham
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Brad Clark
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Leonidas G Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - James W Smallcombe
- Faculty of Medicine and Health, Heat and Health Research Incubator, The University of Sydney, Sydney, NSW, Australia
| | - Richard D Telford
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Ollie Jay
- Faculty of Medicine and Health, Heat and Health Research Incubator, The University of Sydney, Sydney, NSW, Australia
| | - Julien D Périard
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia.
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Deshayes TA, Sodabi DGA, Dubord M, Gagnon D. Shifting focus: Time to look beyond the classic physiological adaptations associated with human heat acclimation. Exp Physiol 2024; 109:335-349. [PMID: 37885125 PMCID: PMC10988689 DOI: 10.1113/ep091207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023]
Abstract
Planet Earth is warming at an unprecedented rate and our future is now assured to be shaped by the consequences of more frequent hot days and extreme heat. Humans will need to adapt both behaviorally and physiologically to thrive in a hotter climate. From a physiological perspective, countless studies have shown that human heat acclimation increases thermoeffector output (i.e., sweating and skin blood flow) and lowers cardiovascular strain (i.e., heart rate) during heat stress. However, the mechanisms mediating these adaptations remain understudied. Furthermore, several possible benefits of heat acclimation for other systems and functions involved in maintaining health and performance during heat stress remain to be elucidated. This review summarizes recent advances in human heat acclimation, with emphasis on recent studies that (1) advanced our understanding of the mechanisms mediating improved thermoeffector output and (2) investigated adaptations that go beyond those classically associated with heat acclimation. We highlight that these studies have contributed to a better understanding of the integrated physiological responses underlying human heat acclimation while leaving key unanswered questions that will need to be addressed in the future.
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Affiliation(s)
- Thomas A. Deshayes
- Montreal Heart InstituteMontréalCanada
- School of Kinesiology and Exercise ScienceUniversité de MontréalMontréalCanada
| | - Dèwanou Gilles Arnaud Sodabi
- Montreal Heart InstituteMontréalCanada
- School of Kinesiology and Exercise ScienceUniversité de MontréalMontréalCanada
| | - Marianne Dubord
- Montreal Heart InstituteMontréalCanada
- School of Kinesiology and Exercise ScienceUniversité de MontréalMontréalCanada
| | - Daniel Gagnon
- Montreal Heart InstituteMontréalCanada
- School of Kinesiology and Exercise ScienceUniversité de MontréalMontréalCanada
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Mason AE, Kasl P, Soltani S, Green A, Hartogensis W, Dilchert S, Chowdhary A, Pandya LS, Siwik CJ, Foster SL, Nyer M, Lowry CA, Raison CL, Hecht FM, Smarr BL. Elevated body temperature is associated with depressive symptoms: results from the TemPredict Study. Sci Rep 2024; 14:1884. [PMID: 38316806 PMCID: PMC10844227 DOI: 10.1038/s41598-024-51567-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/06/2024] [Indexed: 02/07/2024] Open
Abstract
Correlations between altered body temperature and depression have been reported in small samples; greater confidence in these associations would provide a rationale for further examining potential mechanisms of depression related to body temperature regulation. We sought to test the hypotheses that greater depression symptom severity is associated with (1) higher body temperature, (2) smaller differences between body temperature when awake versus asleep, and (3) lower diurnal body temperature amplitude. Data collected included both self-reported body temperature (using standard thermometers), wearable sensor-assessed distal body temperature (using an off-the-shelf wearable sensor that collected minute-level physiological data), and self-reported depressive symptoms from > 20,000 participants over the course of ~ 7 months as part of the TemPredict Study. Higher self-reported and wearable sensor-assessed body temperatures when awake were associated with greater depression symptom severity. Lower diurnal body temperature amplitude, computed using wearable sensor-assessed distal body temperature data, tended to be associated with greater depression symptom severity, though this association did not achieve statistical significance. These findings, drawn from a large sample, replicate and expand upon prior data pointing to body temperature alterations as potentially relevant factors in depression etiology and may hold implications for development of novel approaches to the treatment of major depressive disorder.
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Affiliation(s)
- Ashley E Mason
- Osher Center for Integrative Health, University of California San Francisco, San Francisco, CA, USA.
| | - Patrick Kasl
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, San Diego, CA, USA
| | - Severine Soltani
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, San Diego, CA, USA
| | - Abigail Green
- Neurosciences Graduate Program, University of California San Diego, San Diego, CA, USA
| | - Wendy Hartogensis
- Osher Center for Integrative Health, University of California San Francisco, San Francisco, CA, USA
| | - Stephan Dilchert
- Department of Management, Zicklin School of Business, Baruch College, The City University of New York, New York, NY, USA
| | | | - Leena S Pandya
- Osher Center for Integrative Health, University of California San Francisco, San Francisco, CA, USA
| | - Chelsea J Siwik
- Department of Wellness and Preventative Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - Simmie L Foster
- Depression Clinical and Research Program, Massachusetts General Hospital, Boston, MA, USA
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Maren Nyer
- Depression Clinical and Research Program, Massachusetts General Hospital, Boston, MA, USA
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Christopher A Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Charles L Raison
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Frederick M Hecht
- Osher Center for Integrative Health, University of California San Francisco, San Francisco, CA, USA
| | - Benjamin L Smarr
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, San Diego, CA, USA
- Halıcıoğlu Data Science Institute, University of California San Diego, San Diego, CA, USA
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Gossack-Keenan K, Yeom DS, Kanu J, Hau JP, Rosychuk RJ, Clark D, Bola R, Tze C, Niosco C, Emery H, Yeung P, Hohl CM. Heatstroke presentations to urban hospitals during BC's extreme heat event: lessons for the future. CAN J EMERG MED 2024; 26:111-118. [PMID: 38153655 PMCID: PMC10861625 DOI: 10.1007/s43678-023-00622-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 11/07/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND Climate change is leading to more extreme heat events in temperate climates that typically have low levels of preparedness. Our objective was to describe the characteristics, treatments, and outcomes of adults presenting to hospitals with heatstroke during BC's 2021 heat dome. METHODS We conducted a review of consecutive adults presenting to 7 hospitals in BC's Lower Mainland. We screened the triage records of all patients presenting between June 25th and 30th, 2021 for complaints related to heat, and reviewed the full records of those who met heatstroke criteria. Our primary outcome was in-hospital mortality. We used Mann-Whitney U tests and logistic regression to investigate associations between patient and treatment factors and mortality. RESULTS Among 10,247 consecutive presentations to urban hospitals during the extreme heat event, 1.3% (139; 95% confidence intervals [CI] 1.1-1.6%) met criteria for heatstroke. Of heatstroke patients, 129 (90.6%) were triaged into the two highest acuity levels. Patients with heatstroke had a median age of 84.4 years, with 122 (87.8%) living alone, and 101 (84.2%) unable to activate 911 themselves. A minority (< 5, < 3.6%) of patients presented within 48 h of the onset of extreme heat. Most patients (107, 77.0%) required admission, and 11.5% (16) died in hospital. Hypotension on presentation was associated with mortality (odds ratio [OR] 5.3). INTERPRETATION Heatstroke patients were unable to activate 911 themselves, and most presented with a 48-h delay. This delay may represent a critical window of opportunity for pre-hospital and hospital systems to prepare for the influx of high-acuity resource-intensive patients.
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Affiliation(s)
- Kira Gossack-Keenan
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada.
- Faculty of Medicine, Diamond Health Care Centre, 11th Floor, 2775 Laurel Street, Vancouver, BC, V5Z 1M9, Canada.
| | - David Seonguk Yeom
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Josephine Kanu
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jeffrey P Hau
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
| | | | - Dylan Clark
- Climate Institute Canada, Vancouver, BC, Canada
| | - Rajan Bola
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Caris Tze
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Chris Niosco
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Hayley Emery
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Phillip Yeung
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Corinne M Hohl
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
- Emergency Department, Vancouver General Hospital, Vancouver, BC, Canada
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27
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Willmott AGB, Diment AG, Chung HC, James CA, Maxwell NS, Roberts JD, Gibson OR. Cross-adaptation from heat stress to hypoxia: A systematic review and exploratory meta-analysis. J Therm Biol 2024; 120:103793. [PMID: 38471285 DOI: 10.1016/j.jtherbio.2024.103793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 01/03/2024] [Accepted: 01/12/2024] [Indexed: 03/14/2024]
Abstract
Cross-adaptation (CA) refers to the successful induction of physiological adaptation under one environmental stressor (e.g., heat), to enable subsequent benefit in another (e.g., hypoxia). This systematic review and exploratory meta-analysis investigated the effect of heat acclimation (HA) on physiological, perceptual and physical performance outcome measures during rest, and submaximal and maximal intensity exercise in hypoxia. Database searches in Scopus and MEDLINE were performed. Studies were included when they met the Population, Intervention, Comparison, and Outcome criteria, were of English-language, peer-reviewed, full-text original articles, using human participants. Risk of bias and study quality were assessed using the COnsensus based Standards for the selection of health status Measurement INstruments checklist. Nine studies were included, totalling 79 participants (100 % recreationally trained males). The most common method of HA included fixed-intensity exercise comprising 9 ± 3 sessions, 89 ± 24-min in duration and occurred within 39 ± 2 °C and 32 ± 13 % relative humidity. CA induced a moderate, beneficial effect on physiological measures at rest (oxygen saturation: g = 0.60) and during submaximal exercise (heart rate: g = -0.65, core temperature: g = -0.68 and skin temperature: g = -0.72). A small effect was found for ventilation (g = 0.24) and performance measures (peak power: g = 0.32 and time trial time: g = -0.43) during maximal intensity exercise. No effect was observed for perceptual outcome measures. CA may be appropriate for individuals, such as occupational or military workers, whose access to altitude exposure prior to undertaking submaximal activity in hypoxic conditions is restricted. Methodological variances exist within the current literature, and females and well-trained individuals have yet to be investigated. Future research should focus on these cohorts and explore the mechanistic underpinnings of CA.
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Affiliation(s)
- Ashley G B Willmott
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Alicia G Diment
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Pulmonary Function Laboratory, Norfolk and Norwich University Hospital, Colney Lane, Norwich, Norfolk, United Kingdom.
| | - Henry C Chung
- School of Sport, Rehabilitation and Exercise Sciences (SRES), University of Essex, Colchester, Essex, United Kingdom.
| | - Carl A James
- Hong Kong Sports Institute, Sha Tin, Hong Kong, China; Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
| | - Neil S Maxwell
- Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Justin D Roberts
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom.
| | - Oliver R Gibson
- Centre for Physical Activity in Health and Disease (CPAHD), Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, United Kingdom.
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28
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Morrissey-Basler MC, Eason CM, Clines SH, Kaufman CE, Casa DJ. Perceived challenges and barriers for females working in the heat. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2024; 21:97-107. [PMID: 37801404 DOI: 10.1080/15459624.2023.2268725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
Given rising temperatures, globally, heat exposures and catastrophic heat illnesses are a major concern in laborer and industrial sectors. The purpose of this study was to evaluate the perceptions of females laboring in the heat regarding challenges and barriers encountered in their respective industries while working in the heat. A consensual qualitative research (CQR) design was employed to gain information related to participant occupational and job characteristics, feelings while working in the heat, adjustments made by employers when they work in the heat, and their experience working in the heat specific to their identified sex. Females were eligible to participate if they were currently employed in an environment that required them to work in the heat. Twelve females participated in a single, 45-60 min one-on-one semi-structured interview. Participants reported working in the manufacturing, agriculture, tourism, and railroad industries. Upon completion of data analysis, one primary theme was identified: heat stress mitigation strategies, which were further broken down into two subthemes of formal strategies provided by the employer and informal strategies driven by the employees. Participants indicated there was a lack of heat stress prevention strategies implemented by their employers, which resulted in employees creating their own strategies to protect themselves and their coworkers from heat stress. Results indicated there are limited heat stress prevention strategies that are provided in industries that include females working in the heat. Unique considerations should be made to protect this population from the dangers of heat stress and must go beyond workers protecting themselves.
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Affiliation(s)
- Margaret C Morrissey-Basler
- Department of Health Sciences, Providence College, Providence, Rhode Island
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Christianne M Eason
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Stephanie H Clines
- Department of Athletic Training, Sacred Heart University, Fairfield, Connecticut
| | - Cecilia E Kaufman
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
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29
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Pešić D, Đukić MM, Stanojević I, Živkovć V, Bolevich S, Bolevich S, Jakovljević V. Cardiorespiratory fitness mediates cortisol and lactate responses to winter and summer marches. J Med Biochem 2024; 43:72-85. [PMID: 38496029 PMCID: PMC10943469 DOI: 10.5937/jomb0-44369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/26/2023] [Indexed: 03/19/2024] Open
Abstract
Background The influence of homeostatically regulated physiological processes, including cardiorespiratory fitness (VO2max), on the response to physical stressors such as acclimatisation and marching, remains understudied. We aimed to investigate the effects of summer and winter acclimatisation and marching on cortisol levels and blood lactate, to gain insight into the role of these physiological processes in the stress response. Methods Two groups of young Europeans, classified as poor (PCF; n=9) and good physical condition (GCF; n=21), based on a VO2MAX threshold of 40 mL O2/ kg/min, underwent 2-h March (6-7 km/h) in winter (5˚C) and summer (32˚C). Commercial tests, UniCel DxI Access Cortisol assay and EKF Biosen Clinic/GP assay were used for cortisol and lactate blood measurements (morning samples and those taken immediately after marches), respectively.
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Affiliation(s)
- Deniel Pešić
- Military Medical Academy, Institute of Hygiene, Department of Exercise Physiology, Belgrade
| | - Mirjana M. Đukić
- University of Belgrade, Faculty of Pharmacy, Department of Toxicology, Belgrade
| | - Ivan Stanojević
- Military Medical Academy, Institute of Medical Research, Belgrade
| | - Vladimir Živkovć
- University of Kragujevac, Faculty of Medical Sciences, Department of Physiology, Kragujevac
| | - Sergey Bolevich
- First Moscow State Medical University I. M. Sechenov, Department of Pharmacology, Moscow, Russia
| | - Stefani Bolevich
- First Moscow State Medical University I. M. Sechenov, Department of Pharmacology, Moscow, Russia
| | - Vladimir Jakovljević
- University of Kragujevac, Faculty of Medical Sciences, Department of Physiology, Kragujevac
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30
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Ioannou LG, Tsoutsoubi L, Gkiata P, Brown HA, Periard JD, Mekjavic IB, Kenny GP, Nybo L, Flouris AD. Effect of sportswear on performance and physiological heat strain during prolonged running in moderately hot conditions. Scand J Med Sci Sports 2024; 34:e14520. [PMID: 37839051 DOI: 10.1111/sms.14520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/01/2023] [Accepted: 10/01/2023] [Indexed: 10/17/2023]
Abstract
INTRODUCTION This study examined the impact of different upper-torso sportswear technologies on the performance and physiological heat strain of well-trained and national-level athletes during prolonged running in moderately hot conditions. METHODS A randomized crossover design was employed in which 20 well-trained (n = 16) and national-level (n = 4) athletes completed four experimental trials in moderately hot conditions (35°C, 30% relative humidity). In each trial, participants ran at 70% of their peak oxygen uptake (70% V̇O2peak ) for 60 min, while wearing a different upper-body garment: cotton t-shirt, t-shirt with sweat-wicking fabric, compression t-shirt, and t-shirt with aluminum dots lining the inside of the upper back of the garment. Running speed was adjusted to elicit the predetermined oxygen consumption associated with 70% V̇O2peak . Physiological (core and skin temperatures, total body water loss, and urine specific gravity) and perceptual (thermal comfort and sensation, ratings of perceived exertion, and garment cooling functionality) parameters along with running speed at 70% V̇O2peak were continuously recorded. RESULTS No significant differences were observed between the four garments for running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses (all p > 0.05). The tested athletes reported larger areas of perceived suboptimal cooling functionality in the cotton t-shirt and the t-shirt with aluminum dots relative to the sweat-wicking and compression t-shirts (d: 0.43-0.52). CONCLUSION There were not differences among the tested garments regarding running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses in well-trained and national-level endurance athletes exercising in moderate heat.
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Affiliation(s)
- Leonidas G Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Lydia Tsoutsoubi
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Paraskevi Gkiata
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Harry A Brown
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Julien D Periard
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Igor B Mekjavic
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
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Van Tol Z, Vanos JK, Middel A, Ferguson KM. Concurrent Heat and Air Pollution Exposures among People Experiencing Homelessness. ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:15003. [PMID: 38261303 PMCID: PMC10805133 DOI: 10.1289/ehp13402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/24/2024]
Abstract
BACKGROUND Extreme heat and air pollution are important human health concerns; exposure can affect mental and physical well-being, particularly during periods of co-occurrence. Yet, the impacts on people are largely determined by underlying health conditions, coupled with the length and intensity of exposure. Preexisting adverse health conditions and prolonged exposure times are more common for people experiencing homelessness, particularly those with intersectional identity characteristics (e.g., disease, ability, age, etc.). Partially due to methodological limitations, such as data scarcity, there is a lack of research at the intersection of this at-risk population within the climate-health domain. OBJECTIVES We have three distinct objectives throughout this article: a) to advance critical discussions around the state of concurrent high heat and air pollution exposure research as it relates to people experiencing homelessness; b) to assert the importance of heat and air pollution exposure research among a highly vulnerable, too-often homogenized population-people experiencing homelessness; and c) to underline challenges in this area of study while presenting potential ways to address such shortcomings. DISCUSSION The health insights from concurrent air pollution and heat exposure studies are consequential when studying unhoused communities who are already overexposed to harmful environmental conditions. Without holistic data sets and more advanced methods to study concurrent exposures, appropriate and targeted prevention and intervention strategies cannot be developed to protect this at-risk population. We highlight that a) concurrent high heat and air pollution exposure research among people experiencing homelessness is significantly underdeveloped considering the pressing human health implications; b) the severity of physiological responses elicited by high heat and air pollution are predicated on exposure intensity and time, and thus people without means of seeking climate-controlled shelter are most at risk; and c) collaboration among transdisciplinary teams is needed to resolve data resolution issues and enable targeted prevention and intervention strategies. https://doi.org/10.1289/EHP13402.
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Affiliation(s)
- Zachary Van Tol
- School of Sustainability, Arizona State University, Tempe, Arizona, USA
| | - Jennifer K. Vanos
- School of Sustainability, Arizona State University, Tempe, Arizona, USA
| | - Ariane Middel
- School of Arts, Media and Engineering, Arizona State University, Tempe, Arizona, USA
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Estaphan S, Wadley GD, Todd G, Towstoless M, Hryciw DH, Lexis L, Hayes A, Tangalakis K. Unpacking and validating the "physiological adaptation" core concept of physiology. ADVANCES IN PHYSIOLOGY EDUCATION 2023; 47:831-837. [PMID: 37650145 DOI: 10.1152/advan.00083.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023]
Abstract
A national Task Force of 25 Australian physiology educators used the Delphi protocol to develop seven physiology core concepts that were agreed to nationally. The aim of the current study was to unpack the "physiological adaptation" core concept with the descriptor "organisms adjust and adapt to acute and chronic changes in the internal and external environments across the lifespan." This core concept was unpacked by three Task Force members and a facilitator into four themes and nine subthemes that encompass the role of stressors and disturbed homeostasis in adaptation and the capacity for, and the nature of, the physiological adaptation. Twenty-two Task Force members then provided feedback and rated the themes and subthemes for level of importance and difficulty for students to learn via an online survey using a five-point Likert scale. Seventeen respondents completed all survey questions. For all themes/subthemes, importance was typically rated 1 (Essential) or 2 (Important) (n = 17, means ±SD ranged from 1.1 ± 0.3 to 2.2 ± 0.9), and difficulty was typically rated 3 (Moderately Difficult) (n = 17, means ranged from 2.9 ± 0.7 to 3.4 ± 0.9). Subtle differences in the proportion of importance scores (n = 17, Fisher's exact: P = 0.004, ANOVA: F12,220 = 2.630, P = 0.003; n = 22, Fisher's exact: P = 0.002, ANOVA: F12,281 = 2.743, P < 0.001), but not difficulty scores, were observed between themes/subthemes, and free-text feedback was minor. The results suggest successful unpacking of the physiological adaptation core concept. The themes and subthemes can inform the design of learning outcomes, assessment, and teaching and learning activities that have commonality and consistency across curricula.NEW & NOTEWORTHY An Australian Task Force of physiology educators identified physiological adaptation as a core concept of physiology. It was subsequently unpacked into four themes and nine subthemes. These were rated, by the Task Force, Essential or Important and Moderately Difficult for students to learn. The themes and subthemes can inform the design of learning outcomes, assessments, and teaching and learning activities that have commonality and consistency across curricula.
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Affiliation(s)
- Suzanne Estaphan
- Medical School, ANU College of Health & Medicine, The Australian National University, Acton, Australia
| | - Glenn D Wadley
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia
| | - Gabrielle Todd
- UniSA Clinical & Health Sciences and Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, South Australia, Australia
| | | | - Deanne H Hryciw
- School of Environment and Science, Griffith University, Nathan, Queensland, Australia
| | - Louise Lexis
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia
| | - Alan Hayes
- College of Health & Biomedicine, Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Kathy Tangalakis
- First Year College, Institute for Sustainable Industries & Liveable Cities, Victoria University, Melbourne, Australia
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Bottenheft C, Groen EL, Mol D, Valk PJL, Houben MMJ, Kingma BRM, van Erp JBF. Effects of heat load and hypobaric hypoxia on cognitive performance: a combined stressor approach. ERGONOMICS 2023; 66:2148-2164. [PMID: 36916391 DOI: 10.1080/00140139.2023.2190062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
This study investigates how cognitive performance is affected by the combination of two stressors that are operationally relevant for helicopter pilots: heat load and hypobaric hypoxia. Fifteen participants were exposed to (1) no stressors, (2) heat load, (3) hypobaric hypoxia, and (4) combined heat load and hypobaric hypoxia. Hypobaric hypoxia (13,000 ft) was achieved in a hypobaric chamber. Heat load was induced by increasing ambient temperature to ∼28 °C. Cognitive performance was measured using two multitasks, and a vigilance task. Subjective and physiological data (oxygen saturation, heart rate, core- and skin temperature) were also collected. Mainly heat load caused cognitive performance decline. This can be explained by high subjective heat load and increased skin temperature, which takes away cognitive resources from the tasks. Only the arithmetic subtask was sensitive to hypobaric hypoxia, whereby hypobaric hypoxia caused a further performance decline in addition to the decline caused by heat load.Practitioner summary: Little is known about how multiple environmental stressors interact. This study investigates the combined effects of heat load and hypobaric hypoxia on cognitive performance. An additive effect of heat load and hypobaric hypoxia was found on a arithmetic task, which may be attributed to independent underlying mechanisms.
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Affiliation(s)
- Charelle Bottenheft
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
- Human Media Interaction, Computer Science, University of Twente, Enschede, Netherlands
| | - Eric L Groen
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Douwe Mol
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Pierre J L Valk
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Mark M J Houben
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Boris R M Kingma
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Jan B F van Erp
- Human Media Interaction, Computer Science, University of Twente, Enschede, Netherlands
- Department of Human Machine Teaming, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
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Ravanelli N, Newhouse D, Foster F, Caldwell AR. Agreement between the ventilated capsule and the KuduSmart® device for measuring sweating responses to passive heat stress and exercise. Appl Physiol Nutr Metab 2023; 48:946-953. [PMID: 37566898 DOI: 10.1139/apnm-2023-0149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
The present study assessed agreement between a wireless sweat rate monitor (KuduSmart® device) and the ventilated capsule (VC) technique for measuring: (i) minute-averaged local sweat rate (LSR), (ii) sweating onset, (iii) sudomotor thermosensitivity, and (iv) steady-state LSR, during passive heat stress and exercise. It was hypothesized that acceptable agreement with no bias would be observed between techniques for all assessed sweating characteristics. On two separate occasions for each intervention, participants were either passively heated by recirculating hot water (49 °C) through a tube-lined garment until rectal temperature increased 1 °C over baseline (n = 8), or a 60 min treadmill march at a fixed rate of heat production (∼500 W, n = 9). LSR of the forearm was concurrently measured with a VC and the KuduSmart® device secured within ∼2 cm. Using a ratio scale Bland-Altman analysis with the VC as the reference, the KuduSmart® device demonstrated systematic bias and not acceptable agreement for minute-averaged LSR (1.17 [1.09, 1.27], CV = 44.5%), systematic bias and acceptable agreement for steady-state LSR (1.16 [1.09,1.23], CV = 19.5%), no bias and acceptable agreement for thermosensitivity (1.07 [0.99, 1.16], CV = 23.2%), and no bias and good agreement for sweating onset (1.00 [1.00, 1.00], CV = 11.1%). In total, ≥73% of all minute-averaged LSR observations with the KuduSmart® device (n = 2743) were within an absolute error of <0.2 mg/cm2/min to the VC, the reference minimum detectable change in measurement error of a VC on the forearm. Collectively, the KuduSmart® device may be a satisfactory solution for assessing the sweating response to heat stress where a VC is impractical.
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Affiliation(s)
- Nicholas Ravanelli
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
- Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Douglas Newhouse
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
- Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Fergus Foster
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
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Buguet A, Radomski MW, Reis J, Spencer PS. Heatwaves and human sleep: Stress response versus adaptation. J Neurol Sci 2023; 454:120862. [PMID: 37922826 DOI: 10.1016/j.jns.2023.120862] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 09/21/2023] [Accepted: 10/27/2023] [Indexed: 11/07/2023]
Abstract
The World Meteorological Organization considers a heatwave as "a period of statistically unusual hot weather persisting for a number of days and nights". Accompanying the ongoing global climate change, sharp heatwave bouts occur worldwide, growing in frequency and intensity, and beginning earlier in the season. Heatwaves exacerbate the risk of heat-related illnesses, hence human morbidity and mortality, particularly in vulnerable elderly and children. Heat-related illnesses present a continuum from normothermic (prickly heat, heat edema, heat cramps, heat tetany) to hyperthermic syndromes (from heat syncope and heat exhaustion to lethal heat stroke). Heat stroke may occur through passive heating and/or exertional exercise. "Normal sleep", such as observed in temperate conditions, is altered during heatwaves. Brisk excessive heat bouts shorten and fragment human sleep. Particularly, deep N3 sleep (formerly slow-wave sleep) and REM sleep are depleted, such as in other stressful situations. The resultant sleep loss is deleterious to cognitive performance, emotional brain function, behavior, and susceptibility to chronic health conditions and infectious diseases. Our group has previously demonstrated that sleep constitutes an adaptive mechanism during climatic heat acclimatization. In parallel, artificial heat acclimation procedures have been proposed in sports and military activities, and for the elderly. Other preventive actions should be considered, such as education and urban heat island cooling (vegetation, white paint), thus avoiding energy-hungry air conditioning.
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Affiliation(s)
- Alain Buguet
- Invited Scientist, Malaria Research Unit, UMR 5246 CNRS, Claude-Bernard Lyon-1 University, 69622 Villeurbanne, France.
| | - Manny W Radomski
- Professor Emeritus at the University of Toronto, Apt n° 2501, 2010 Islington Avenue, Toronto, ON M9P3S8, Canada
| | - Jacques Reis
- University of Strasbourg, 67000 Strasbourg, France; Association RISE, 3 rue du Loir, 67205 Oberhausbergen, France
| | - Peter S Spencer
- Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, USA.
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Palejwala Z, Wallman KE, Landers GJ, Anbalagan P, Wood FM, Maloney SK. Living in Western Australia induces some physiological adaptations of seasonal acclimatisation in the surgical burns team. Temperature (Austin) 2023; 11:110-122. [PMID: 38846522 PMCID: PMC11152095 DOI: 10.1080/23328940.2023.2281210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/02/2023] [Indexed: 06/09/2024] Open
Abstract
Seasonal acclimatization is known to result in adaptations that can improve heat tolerance. Staff who operate on burn injuries are exposed to thermally stressful conditions and seasonal acclimatization may improve their thermoeffector responses during surgery. Therefore, the aim of this study was to assess the physiological and perceptual responses of staff who operate on burn injuries during summer and winter, to determine whether they become acclimatized to the heated operating theater. Eight staff members had physiological and perceptual responses compared during burn surgeries conducted in thermoneutral (CON: 24.1 ± 1.2°C, 45 ± 7% relative humidity [RH]) and heated (HOT: 31.3 ± 1.6°C, 44 ± 7% RH) operating theaters, in summer and winter. Physiological parameters that were assessed included core temperature, heart rate, total sweat loss, sweat rate, and urinary specific gravity. Perceptual responses included ratings of thermal sensation and comfort. In summer, CON compared to winter CON, baseline (85 ± 15 bpm VS 94 ± 18 bpm), mean (84 ± 16 bpm VS 93 ± 18 bpm), and peak HR (94 ± 17 bpm VS 105 ± 19 bpm) were lower (p < 0.05), whereas core temperature was not different between seasons in either condition (p > 0.05). In HOT, ratings of discomfort were higher in summer (15 ± 3) than winter (13 ± 3; p > 0.05), but ratings of thermal sensation and sweat rate were similar between seasons (p > 0.05). The surgical team in burns in Western Australia can obtain some of the physiological adaptations that result from seasonal acclimatization, but not all. That is most likely due to a lower than required amount of outdoor heat exposure in summer, to induce all physiological and perceptual adaptations.
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Affiliation(s)
- Zehra Palejwala
- School of Human Sciences (Sports Science Exercise and Health), The University of Western Australia, Crawley, WA, Australia
| | - Karen E. Wallman
- School of Human Sciences (Sports Science Exercise and Health), The University of Western Australia, Crawley, WA, Australia
| | - Grant J. Landers
- School of Human Sciences (Sports Science Exercise and Health), The University of Western Australia, Crawley, WA, Australia
| | - Prashan Anbalagan
- School of Human Sciences (Sports Science Exercise and Health), The University of Western Australia, Crawley, WA, Australia
| | - Fiona M. Wood
- Burn service of Western Australia, WA Department of Health, Nedlands, WA, Australia
- Burn Injury Research Unit, University of Western Australia, and Burn service of WA South Metropolitan Health Service, Perth, WA, Australia
| | - Shane K. Maloney
- School of Human Sciences (Sports Science Exercise and Health), The University of Western Australia, Crawley, WA, Australia
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Goulet EDB, Claveau P, Simoneau IL, Deshayes TA, Jolicoeur-Desroches A, Aloui F, Hoffman MD. Repeatability of Ad Libitum Water Intake during Repeated 1 h Walking/Jogging Exercise Sessions Conducted under Hot Ambient Conditions. Nutrients 2023; 15:4500. [PMID: 37960153 PMCID: PMC10650651 DOI: 10.3390/nu15214500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
A drinking strategy aiming to replace a given percentage of the sweat losses incurred during exercise should result in reproducible fluid intake volume and, hence, fluid balance from one exercise session to the other performed under similar scenarios. Whether this may also be the case with ad libitum drinking during exercise is unclear. We characterized the repeatability of ad libitum water intake during repeated 1 h exercise sessions and examined its effect over time on fluid balance and selected physiological functions and perceptual sensations. Twelve (3 women) healthy individuals participated in this study. At weekly intervals, they completed four 2 × 30 min walking/jogging exercise bouts (55% V˙O2max, 40 °C, 20-30% relative humidity) interspersed by a 3 min recovery period. During exercise, participants consumed water (20 °C) ad libitum. There were no significant differences among the four exercise sessions for absolute water intake volume (~1000 mL·h-1), percent body mass loss (~0.4%), sweat rate (~1300 mL·h-1) and percent of sweat loss replaced by water intake (~80%). Heart rate, rectal temperature, and perceived thirst and heat stress did not differ significantly between the first and fourth exercise sessions. Perceived exertion was significantly lower during the fourth vs. the first exercise session, but the difference was trivial (<1 arbitrary unit). In conclusion, ad libitum water intake during four successive identical 1 h walking/jogging sessions conducted in the heat will result in similar water intake volumes and perturbations in fluid balance, heart rate, rectal temperature, and perceived thirst, heat stress and exertion.
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Affiliation(s)
- Eric D. B. Goulet
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada; (P.C.); (T.A.D.); (A.J.-D.); (F.A.)
- Research Center on Aging, University of Sherbrooke, Sherbrooke, PQ J1H 4C4, Canada
| | - Pascale Claveau
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada; (P.C.); (T.A.D.); (A.J.-D.); (F.A.)
| | - Ivan L. Simoneau
- Centre de Recherche et de Formation par Simulation, Cégep of Sherbrooke, Sherbrooke, PQ J1E 4K1, Canada;
| | - Thomas A. Deshayes
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada; (P.C.); (T.A.D.); (A.J.-D.); (F.A.)
- Research Center on Aging, University of Sherbrooke, Sherbrooke, PQ J1H 4C4, Canada
| | - Antoine Jolicoeur-Desroches
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada; (P.C.); (T.A.D.); (A.J.-D.); (F.A.)
| | - Fedi Aloui
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada; (P.C.); (T.A.D.); (A.J.-D.); (F.A.)
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Corbett J, Young JS, Tipton MJ, Costello JT, Williams TB, Walker EF, Lee BJ, Stevens CE. Molecular biomarkers for assessing the heat-adapted phenotype: a narrative scoping review. J Physiol Sci 2023; 73:26. [PMID: 37848829 DOI: 10.1186/s12576-023-00882-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/03/2023] [Indexed: 10/19/2023]
Abstract
Heat acclimation/acclimatisation (HA) mitigates heat-related decrements in physical capacity and heat-illness risk and is a widely advocated countermeasure for individuals operating in hot environments. The efficacy of HA is typically quantified by assessing the thermo-physiological responses to a standard heat acclimation state test (i.e. physiological biomarkers), but this can be logistically challenging, time consuming, and expensive. A valid molecular biomarker of HA would enable evaluation of the heat-adapted state through the sampling and assessment of a biological medium. This narrative review examines candidate molecular biomarkers of HA, highlighting the poor sensitivity and specificity of these candidates and identifying the current lack of a single 'standout' biomarker. It concludes by considering the potential of multivariable approaches that provide information about a range of physiological systems, identifying a number of challenges that must be overcome to develop a valid molecular biomarker of the heat-adapted state, and highlighting future research opportunities.
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Affiliation(s)
- J Corbett
- Extreme Environments Laboratory, School of Sport Health and Exercise Sciences, University of Portsmouth, Portsmouth, UK.
| | - J S Young
- National Horizons Centre, Teesside University, Darlington, UK
| | - M J Tipton
- Extreme Environments Laboratory, School of Sport Health and Exercise Sciences, University of Portsmouth, Portsmouth, UK
| | - J T Costello
- Extreme Environments Laboratory, School of Sport Health and Exercise Sciences, University of Portsmouth, Portsmouth, UK
| | - T B Williams
- Extreme Environments Laboratory, School of Sport Health and Exercise Sciences, University of Portsmouth, Portsmouth, UK
| | - E F Walker
- Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - B J Lee
- Occupational and Environmental Physiology Group, Centre for Sport, Exercise and Life Sciences, Faculty of Health and Life Sciences, Coventry University, Coventry, UK
| | - C E Stevens
- Extreme Environments Laboratory, School of Sport Health and Exercise Sciences, University of Portsmouth, Portsmouth, UK
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Deshayes TA, Périard JD. Regular physical activity across the lifespan to build resilience against rising global temperatures. EBioMedicine 2023; 96:104793. [PMID: 37689024 PMCID: PMC10498184 DOI: 10.1016/j.ebiom.2023.104793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/11/2023] Open
Abstract
Population aging, high prevalence of non-communicable diseases, physical inactivity, and rising global temperatures are some of the most pressing issues in public health of the current century. Such trends suggest that individuals increasingly less equipped to tolerate heat will be increasingly exposed to it, which from a public health perspective is alarming. Nonetheless, future impacts of extreme heat events will depend not only on the magnitude of climate change, but on our ability to adapt by becoming less sensitive and vulnerable. Although physical activity's role in mitigating climate change has received attention, its potential contribution to climate change adaptation and resilience remains largely unaddressed. Accordingly, in this viewpoint, we discuss how regular physical activity throughout life could have an important contribution to adapting to rising global temperatures, allowing to be better equipped to cope with heat-related health hazards and increasing individual and community resilience. This viewpoint constitutes a call for more research into the contribution that physical activity can have in adapting to rising global temperatures and, more broadly, to climate change.
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Affiliation(s)
- Thomas A Deshayes
- Montreal Heart Institute, Montréal, Canada; School of Kinesiology and Exercise Science, Université de Montréal, Montréal, Canada.
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
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Bernard TE, Ashley CD, Wolf ST, Odera AM, Lopez RM, Kenney WL. Distribution of upper limit of the prescriptive zone values for acclimatized and unacclimatized individuals. J Appl Physiol (1985) 2023; 135:601-608. [PMID: 37498291 PMCID: PMC10538976 DOI: 10.1152/japplphysiol.00724.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 06/27/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023] Open
Abstract
Heat stress has an adverse impact on worker health and well-being, and the effects will increase with more frequent and severe heat events associated with global warming. Acclimatization to heat stress is widely considered to be a critical mitigation strategy and wet bulb globe temperature- (WBGT-) based occupational standards and guidelines contain adjustments for acclimatization. The purpose here was to 1) compare the mean values for the upper limit of the prescriptive zone (ULPZ, below which the rise in core temperature is minimal) between unacclimatized and acclimatized men and women; 2) demonstrate that the change in the occupational exposure limit (ΔOEL) due to acclimatization is independent of metabolic rate; 3) examine the relation between ΔOEL and body surface area (BSA); and 4) compare the exposure-response curves between unacclimatized and acclimatized populations. Empirically derived ULPZ data for unacclimatized participants from Pennsylvania State University (PSU) and acclimatized participants from University of South Florida (USF) were used to explore the difference between unacclimatized and acclimatized heat exposure limits. The findings provide support for a constant 3°C WBGT OEL decrease to account for unacclimatized workers. Body surface area explained part of the difference in ULPZ values between men and women. In addition, the pooled PSU and USF data provide insight into the distribution of individual values for the ULPZ among young, healthy unacclimatized and acclimatized populations in support of occupational heat stress guidelines.NEW & NOTEWORTHY Occupational exposure limit guidelines using wet bulb globe temperature (WBGT) distinguish between acclimatized and unacclimatized workers with about a 3°C difference between them. For the first time, empirical data from two laboratories provide support for acclimatization state adjustments. Using a constant difference rather than increasing differences with metabolic rate better describes the limit for unacclimatized participants. Furthermore, the lower upper limit of the prescriptive zone (ULPZ) values set forth for women do not relate to fitness level but are partly explained by their smaller body surface area (BSA). An examination of individual ULPZ values suggests that many unacclimatized individuals should be able to sustain safe work at the exposure limit for acclimatized workers.
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Affiliation(s)
- Thomas E Bernard
- College of Public Health, University of South Florida, Tampa, Florida, United States
| | - Candi D Ashley
- Exercise Science Program, College of Education, University of South Florida, Tampa, Florida, United States
| | - S Tony Wolf
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Ayub M Odera
- College of Public Health, University of South Florida, Tampa, Florida, United States
| | - Rebecca M Lopez
- School of Physical Therapy & Rehabilitation Sciences, Department of Orthopaedics & Sports Medicine, University of South Florida, Tampa, Florida, United States
| | - W Larry Kenney
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
- Graduate Program in Physiology, The Pennsylvania State University, University Park, Pennsylvania, United States
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Tebeck ST, Buckley JD, Stanley J. Longitudinal haematological responses to training load and heat acclimation preceding a male team pursuit cycling world record. Eur J Sport Sci 2023; 23:1859-1867. [PMID: 36404735 DOI: 10.1080/17461391.2022.2150896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study evaluated relationships between changes in training load, haematological responses, and endurance exercise performance during temperate and heat acclimation (HA) training preceding a male team cycling pursuit world record (WR). Haemoglobin mass (Hbmass) and concentration ([Hb]), plasma volume (PV) and blood volume (BV) were assessed in nine male track endurance cyclists (∼3 occasions per month) training in temperate conditions (247-142 days prior to the WR) to establish responses to differing acute (ATL) and chronic (CTL) training loads. Testing was performed again pre- and post-HA (22-28 days prior to the WR). Endurance performance (V̇O₂max, 4MMP, lactate threshold 1 and 2) was assessed on three occasions (238-231, 189-182 and 133-126 days prior to the WR). In temperate conditions, CTL was associated with Hbmass (B = 0.62, P = 0.02), PV (B = 4.49, P = 0.01) and BV (B = 6.51, P = 0.04) but not [Hb] (B = -0.01, P = 0.17). ATL was associated with PV (B = 2.28, P < 0.01), BV (B = 2.63, P = 0.04) and [Hb] (B = -0.01, P = 0.04) but not Hbmass (B = 0.10, P = 0.41). During HA, PV increased 8.2% (P < 0.01), while Hbmass, CTL and ATL were unchanged. Hbmass and [Hb] were associated with all performance outcomes (P < 0.05), except V̇O2max. PV and BV were not associated with performance outcomes. During temperate training, changes in Hbmass were most strongly associated with changes in CTL. Both CTL and ATL were associated with changes in PV, but HA was associated with increased PV and maintenance of Hbmass without increasing ATL or CTL. In practical terms, maintaining high CTL and high Hbmass might be beneficial for improving endurance performance.HIGHLIGHTSChanges in haemoglobin mass were associated with endurance exercise performance and changes in chronic training load in temperate conditions.Heat acclimation increased plasma volume and maintained haemoglobin mass independently of chronic training load.Chronic training loads and haemoglobin mass should be increased to improve endurance exercise performance.Heat acclimation may optimise haematological adaptations when training load is reduced.
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Affiliation(s)
- Samuel T Tebeck
- Department of Sports Science, South Australian Sports Institute, Adelaide, Australia
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, Adelaide, Australia
| | - Jonathan D Buckley
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, Adelaide, Australia
| | - Jamie Stanley
- Department of Sports Science, South Australian Sports Institute, Adelaide, Australia
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, Adelaide, Australia
- Australian Cycling Team, Cycling Australia, Adelaide, Australia
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Bennett S, Tiollier E, Guibert E, Morales-Artacho A, Lalire P, Owens DJ, Morton JP, Brocherie F, Louis J. Environmental heat stress offsets adaptation associated with carbohydrate periodization in trained male triathletes. Scand J Med Sci Sports 2023; 33:1677-1689. [PMID: 37322619 DOI: 10.1111/sms.14430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/17/2023]
Abstract
PURPOSE Carbohydrate (CHO) intake periodization via the sleep low train low (SL-TL) diet-exercise model increases fat oxidation during exercise and may enhance endurance-training adaptation and performance. Conversely, training under environmental heat stress increases CHO oxidation, but the potential of combined SL-TL and heat stress to enhance metabolic and performance outcomes is unknown. METHODS Twenty-three endurance-trained males were randomly assigned to either control (n = 7, CON), SL-TL (n = 8, SLTemp ) or SL-TL + heat stress (n = 8, SLHeat ) groups and prescribed identical 2-week cycling training interventions. CON and SLTemp completed all sessions at 20°C, but SLHeat at 35°C. All groups consumed matched CHO intake (6 g·kg-1 ·day-1 ) but timed differently to promote low CHO availability overnight and during morning exercise in both SL groups. Submaximal substrate utilization was assessed (at 20°C), and 30-min performance tests (at 20 and 35°C) were performed Pre-, Post-, and 1-week post-intervention (Post+1). RESULTS SLTemp improved fat oxidation rates at 60% MAP (~66% VO2peak ) at Post+1 compared with CON (p < 0.01). Compared with SLTemp , fat oxidation rates were significantly lower in SLHeat at Post (p = 0.02) and Post+1 (p < 0.05). Compared with CON, performance was improved at Post in SLTemp in temperate conditions. Performance was not different between any groups or time points in hot conditions. CONCLUSION SL-TL enhanced metabolic adaptation and performance compared with CON and combined SL-TL and heat stress. Additional environmental heat stress may impair positive adaptations associated with SL-TL.
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Affiliation(s)
- Samuel Bennett
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, UK
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Eve Tiollier
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Elodie Guibert
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Antonio Morales-Artacho
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Paul Lalire
- French Triathlon Federation (FFTri), Saint-Denis, France
| | - Daniel J Owens
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, UK
| | - James P Morton
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, UK
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Julien Louis
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, UK
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
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Périard JD, Girard O, Townsend N, Bourdon P, Cocking S, Ihsan M, Lacome M, Nichols D, Travers G, Wilson MG, Piscione J, Racinais S. Hematological Adaptations Following a Training Camp in Hot and/or Hypoxic Conditions in Elite Rugby Union Players. Int J Sports Physiol Perform 2023; 18:1053-1061. [PMID: 37553108 DOI: 10.1123/ijspp.2023-0166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/30/2023] [Accepted: 07/08/2023] [Indexed: 08/10/2023]
Abstract
PURPOSE To investigate the effects of a training camp with heat and/or hypoxia sessions on hematological and thermoregulatory adaptations. METHODS Fifty-six elite male rugby players completed a 2-week training camp with 5 endurance and 5 repeated-sprint sessions, rugby practice, and resistance training. Players were separated into 4 groups: CAMP trained in temperate conditions at sea level, HEAT performed the endurance sessions in the heat, ALTI slept and performed the repeated sprints at altitude, and H + A was a combination of the heat and altitude groups. RESULTS Blood volume across all groups increased by 140 mL (95%CI, 42-237; P = .006) and plasma volume by 97 mL (95%CI 28-167; P = .007) following the training camp. Plasma volume was 6.3% (0.3% to 12.4%) higher in HEAT than ALTI (P = .034) and slightly higher in HEAT than H + A (5.6% [-0.3% to 11.7%]; P = .076). Changes in hemoglobin mass were not significant (P = .176), despite a ∼1.2% increase in ALTI and H + A and a ∼0.7% decrease in CAMP and HEAT. Peak rectal temperature was lower during a postcamp heat-response test in HEAT (0.3 °C [0.1-0.5]; P = .010) and H + A (0.3 °C [0.1-0.6]; P = .005). Oxygen saturation upon waking was lower in ALTI (3% [2% to 5%]; P < .001) and H + A (4% [3% to 6%]; P < .001) than CAMP and HEAT. CONCLUSION Although blood and plasma volume increased following the camp, sleeping at altitude impeded the increase when training in the heat and only marginally increased hemoglobin mass. Heat training induced adaptations commensurate with partial heat acclimation; however, combining heat training and altitude training and confinement during a training camp did not confer concomitant hematological adaptations.
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Affiliation(s)
- Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT,Australia
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
| | - Olivier Girard
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA,Australia
| | - Nathan Townsend
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha,Qatar
| | - Pitre Bourdon
- Department of Sport Science, ASPIRE, Academy for Sports Excellence, Doha,Qatar
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, SA,Australia
| | - Scott Cocking
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- Department of Sport Science, ASPIRE, Academy for Sports Excellence, Doha,Qatar
| | - Mohammed Ihsan
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
| | - Mathieu Lacome
- Department of Research, Sport Laboratory, Expertise and Performance, French Institute of Sports (INSEP), Paris,France
- Department of Performance and Analytics, Parma Calcio, Parma,Italy
| | - David Nichols
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
| | - Gavin Travers
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- Space Medicine Team, European Astronaut Center, Köln,Germany
| | - Mathew G Wilson
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- Institute of Sport, Exercise and Health, University College London, London,United Kingdom
| | - Julien Piscione
- Department of Research, Sport Laboratory, Expertise and Performance, French Institute of Sports (INSEP), Paris,France
| | - Sebastien Racinais
- Department of Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, Doha,Qatar
- Department of Research, Sport Laboratory, Expertise and Performance, French Institute of Sports (INSEP), Paris,France
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Wheelock CE, Looney DP, Potter AW, Pryor RR, Pryor JL, Florian J, Hostler D. Diver Underwater Cycling Endurance After Short-Term Warm and Hot Water Acclimation. Mil Med 2023; 188:3071-3078. [PMID: 35822881 DOI: 10.1093/milmed/usac204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/11/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION It is unclear whether immersion heat acclimation benefits exercise in warm water conditions. This study examined the effects of heat acclimation strategies on heart rate (HR), core temperature, and time to exhaustion (TTE) during cycling exercise in varying warm water conditions. METHODS Twenty male divers completed this study at the Navy Experimental Diving Unit. Subjects were randomly assigned to one of two 9-day heat acclimation groups. The first group (WARM; n = 10) cycled for 2 hours at 50 W in 34.4 °C water, while the second group (HOT; n = 10) cycled for 1 hour against minimal resistance in 36.7 °C water. Following acclimation, TTE was tested by underwater cycling (30 W) in 35.8 °C, 37.2 °C, and 38.6 °C water. RESULTS Throughout acclimation, the rate of core temperature rise in the first 30 minutes of exercise increased (P = .02), but the maximum core temperature reached was not different for either group. Time to exhaustion (TTE) was reduced, and the rate of core temperature rise during performance testing increased (both P < .001) with increasing water temperature but was not different between groups. Core temperature and HR increased throughout performance testing in each water condition and were lower in the HOT compared to the WARM acclimation group (all P < .05) with the exception of core temperature in the 37.2 °C condition. CONCLUSIONS Underwater exercise performance did not differ between the two acclimation strategies. This study suggests that passive acclimation to a higher water temperature may improve thermoregulatory and cardiovascular responses to exercise in warm water. Hot water immersion adaptations are dependent on exercise intensity and water temperature.
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Affiliation(s)
- Courtney E Wheelock
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - David P Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA 01760, USA
| | - Adam W Potter
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA 01760, USA
| | - Riana R Pryor
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - J Luke Pryor
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - John Florian
- Navy Experimental Diving Unit (NEDU), Panama City, FL 32407, USA
| | - David Hostler
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
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Patel S, Mittal R, Kumar N, Galor A. The environment and dry eye-manifestations, mechanisms, and more. FRONTIERS IN TOXICOLOGY 2023; 5:1173683. [PMID: 37681211 PMCID: PMC10482047 DOI: 10.3389/ftox.2023.1173683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/07/2023] [Indexed: 09/09/2023] Open
Abstract
Dry eye disease (DED) is a multifactorial condition that often presents with chronic symptoms of pain (that can be characterized as "dryness," "burning," and "irritation," to name a few) and/or fluctuating or poor-quality vision. Given its multifactorial nature, several pathophysiologic mechanisms have been identified that can underlie symptoms, including tear film, ocular surface, and/or corneal somatosensory nerve abnormalities. Research has focused on understanding how environmental exposures can increase the risk for DED flares and negatively impact the tear film, the ocular surface, and/or nerve health. Given that DED is a common condition that negatively impacts physical and mental functioning, managing DED requires multiple strategies. These can include both medical approaches and modulating adverse environmental conditions, the latter of which may be a cost-effective way to avoid DED flares. Thus, an understanding of how environmental exposures relate to disease is important. This Review summarizes research on the relationships between environmental exposures and DED, in the hope that this information will engage healthcare professionals and patients to consider environmental manipulations in their management of DED.
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Affiliation(s)
- Sneh Patel
- Division of Physical Medicine and Rehabilitation, Veterans Affairs (VA) Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- University of California Los Angeles (UCLA), Los Angeles, CA, United States
| | - Rhiya Mittal
- University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, United States
| | - Naresh Kumar
- Department of Public Health Sciences, University of Miami, Miami, FL, United States
| | - Anat Galor
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, United States
- Ophthalmology and Research Services, Miami VA Medical Center, Miami, FL, United States
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Zhang T, Huang R, Yang M, Lin G, Ma X, Wang X, Huang Q. Perceptions of the health risk from hot days and the cooling effect of urban green spaces: a case study in Xi'an, China. Front Public Health 2023; 11:1211164. [PMID: 37674680 PMCID: PMC10477602 DOI: 10.3389/fpubh.2023.1211164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/08/2023] [Indexed: 09/08/2023] Open
Abstract
Background Hot days are one of the typical threats to human health and sustainable cities. The exploration of residents' perceptions of thermal environment and its mitigation measures will support the health risk prevention. Methods A survey with a combination of closed-ended and open-ended questions was conducted in July 2021 among 13 urban parks in Xi'an City, China. With the help of ANOVA and ordinal logistic regression, this study investigated the influencing factors both on residents' health risk perception of hot days and their perception of the effect of urban ecological landscape on reducing the thermal risk. The relationship between health risk perception and residents' needs of urban ecological construction was also explored. Results According to 325 valid questionnaires, the male-female ratio of respondents was found to be 1:0.87, young people aged 18-29 (26.46%), the retirees (27.08%) and the ones with undergraduate education (33.23%) were, relatively, the largest groups. The results show that 92.31% of the respondents believed that their daily lives were under the influence of hot days. Housing types, occupation, cooling equipment at work, and outdoor working hours all had a significant impact on their high temperature perceptions. The proportion of respondents who were under a huge health risk and sought medical treatment due to hot days was 30.16% and 44.92%, respectively. Women were 18.52 and 2.33 times more likely to suffer health threats and experience discomforts than men. Furthermore, 73.23% of the respondents believed that the urban ecological landscapes in Xi'an had an enhanced cooling effect in recent years. Compared with the morphological characteristics, residents' recognition of the restriction of landscape's area on its cooling effect was higher, and the residence duration showed a significant influence. Conclusion The cooling effect of green spaces and water effectively resisted urban thermal threats, and residents' needs of the urban ecological landscapes was associated with their health risk perceptions of hot days. In the future, it is necessary to promote the early warning of hot days, meanwhile, the optimization of landscape patterns of green infrastructures should be implemented in urban planning for the purposes of residents' health risk prevention.
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Affiliation(s)
- Tian Zhang
- Northwest Land and Resource Research Center, Shaanxi Normal University, Xi’an, China
| | - Rong Huang
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
| | - Mei Yang
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
| | - Guohua Lin
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
| | - Xiaoyan Ma
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
| | - Xuan Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
| | - Qian Huang
- School of Geography and Tourism, Shaanxi Normal University, Xi’an, China
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Spector JT, Sampson L, Flunker JC, Adams D, Bonauto DK. Occupational heat-related illness in Washington State: A descriptive study of day of illness and prior day ambient temperatures among cases and clusters, 2006-2021. Am J Ind Med 2023; 66:623-636. [PMID: 37291066 PMCID: PMC10330917 DOI: 10.1002/ajim.23506] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/19/2023] [Indexed: 06/10/2023]
Abstract
BACKGROUND Insufficient heat acclimatization is a risk factor for heat-related illness (HRI) morbidity, particularly during periods of sudden temperature increase. We sought to characterize heat exposure on days before, and days of, occupational HRIs. METHODS A total of 1241 Washington State workers' compensation State Fund HRI claims from 2006 to 2021 were linked with modeled parameter-elevation regressions on independent slopes model (PRISM) meteorological data. We determined location-specific maximum temperatures (Tmax,PRISM ) on the day of illness (DOI) and prior days, and whether the Tmax,PRISM was ≥10.0°F (~5.6°C) higher than the average of past 5 days ("sudden increase") for each HRI claim. Claims occurring on days with ≥10 HRI claims ("clusters") were compared with "non-cluster" claims using t tests and χ2 tests. RESULTS Seventy-six percent of analyzed HRI claims occurred on days with a Tmax,PRISM ≥ 80°F. Claims occurring on "cluster" days, compared to "non-cluster" days, had both a significantly higher mean DOI Tmax,PRISM (99.3°F vs. 85.8°F [37.4°C vs. 29.9°C], t(148) = -18, p < 0.001) and a higher proportion of "sudden increase" claims (80.2% vs. 24.3%, χ2 [1] = 132.9, p < 0.001). Compared to "cluster" days, HRI claims occurring during the 2021 Pacific Northwest "heat dome" had a similar increased trajectory of mean Tmax,PRISM on the days before the DOI, but with higher mean Tmax,PRISM. CONCLUSIONS: Occupational HRI risk assessments should consider both current temperatures and changes in temperatures relative to prior days. Heat prevention programs should include provisions to address acclimatization and, when increases in temperature occur too quickly to allow for sufficient acclimatization, additional precautions.
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Affiliation(s)
- June T. Spector
- Safety and Health Assessment and Research for Prevention (SHARP) Program, Washington State Department of Labor and Industries, Olympia, Washington, USA
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Luke Sampson
- Safety and Health Assessment and Research for Prevention (SHARP) Program, Washington State Department of Labor and Industries, Olympia, Washington, USA
- CSTE Applied Epidemiology Fellowship Program, Council of State and Territorial Epidemiologists, Atlanta, Georgia, USA
| | - John C. Flunker
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Darrin Adams
- Safety and Health Assessment and Research for Prevention (SHARP) Program, Washington State Department of Labor and Industries, Olympia, Washington, USA
| | - David K. Bonauto
- Safety and Health Assessment and Research for Prevention (SHARP) Program, Washington State Department of Labor and Industries, Olympia, Washington, USA
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Gouttebarge V, Duffield R, den Hollander S, Maughan R. Protective guidelines and mitigation strategies for hot conditions in professional football: starting 11 Hot Tips for consideration. BMJ Open Sport Exerc Med 2023; 9:e001608. [PMID: 37492782 PMCID: PMC10364156 DOI: 10.1136/bmjsem-2023-001608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
Elevated heat, humidity and solar load combined with low air movement independently and additively impair performance, increase the perception of effort and the risk of heat-related illnesses. For the specific context of professional football, the Fédération Internationale de Football Association (FIFA) heat guidelines are often used as the default policy. Still, these seem less protective than guidelines in other sports or from countries traditionally exposed to extreme hot conditions. Following several high-profile international and continental competitions played in hot conditions (eg, 2014 FIFA World Cup Brazil), a series of cross-sectional studies showed that national team players and their managers unanimously mentioned that the hot and humid conditions during these matches made it difficult as a team to perform. Such a concern is likely to be relevant for the upcoming 2026 FIFA World Cup that will be held in the traditional June-July window across 16 host cities in Canada, Mexico and USA. Therefore, to better protect players' health and performance during training and match play in hot conditions, we present our starting 11 Hot Tips that should be considered and facilitated by governing bodies, competition organisers, clubs, staff members and players.
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Affiliation(s)
- Vincent Gouttebarge
- Football Players Worldwide (FIFPRO), Hoofddorp, Netherlands
- Amsterdam UMC location University of Amsterdam, Department of Orthopedic Surgery and Sports Medicine, Meibergdreef 9, Amsterdam, Netherlands
- Amsterdam Collaboration on Health & Safety in Sports (ACHSS), IOC Research Center, Amsterdam, Netherlands
- Section Sports Medicine, University of Pretoria, Pretoria, South Africa
| | - Rob Duffield
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney, Sydney, New South Wales, Australia
| | | | - Ron Maughan
- School of Medicine, St Andrews University, St Andrews, UK
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Matias AA, Albin IF, Glickman L, Califano PA, Faller JM, Layec G, Ives SJ. Impact of high intensity interval exercise with and without heat stress on cardiovascular and aerobic performance: a pilot study. BMC Sports Sci Med Rehabil 2023; 15:83. [PMID: 37434243 DOI: 10.1186/s13102-023-00682-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 06/21/2023] [Indexed: 07/13/2023]
Abstract
BACKGROUND Heat stress during aerobic exercise training may offer an additional stimulus to improve cardiovascular function and performance in a cool-temperate environment. However, there is a paucity of information on the additive effects of high-intensity interval exercise (HIIE) and acute heat stress. We aimed to determine the effects of HIIE in combination with acute heat stress on cardiovascular function and exercise performance. METHODS Twelve active (peak O2 consumption [VO2peak]: 47 ± 8 ml·O2/min/kg) young adults were counterbalanced to six sessions of HIIE in hot (HIIE-H, 30 ± 1 °C, 50 ± 5% relative humidity [RH]) or temperate conditions (HIIE-T, 20 ± 2 °C, 15 ± 10% RH). Resting heart rate (HR), HR variability (HRV), central (cBP) and peripheral blood pressure (pBP), peripheral mean arterial pressure (pMAP), pulse wave velocity (PWV), VO2peak, and 5-km treadmill time-trial were measured pre- and post-training. RESULTS Resting HR and HRV were not significantly different between groups. However, expressed as percent change from baseline, cSBP (HIIE-T: + 0.9 ± 3.6 and HIIE-H: -6.6 ± 3.0%, p = 0.03) and pSBP (HIIE-T: -2.0 ± 4.6 and HIIE-H: -8.4 ± 4.7%, p = 0.04) were lower in the heat group. Post-training PWV was also significantly lower in the heat group (HIIE-T: + 0.4% and HIIE-H: -6.3%, p = 0.03). Time-trial performance improved with training when data from both groups were pooled, and estimated VO2peak was not significantly different between groups (HIIE-T: 0.7% and HIIE-H: 6.0%, p = 0.10, Cohen's d = 1.4). CONCLUSIONS The addition of acute heat stress to HIIE elicited additive adaptations in only cardiovascular function compared to HIIE alone in active young adults in temperate conditions, thus providing evidence for its effectiveness as a strategy to amplify exercise-induced cardiovascular adaptations.
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Affiliation(s)
- Alexs A Matias
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
| | - Isabelle F Albin
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Leah Glickman
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Peter A Califano
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Justin M Faller
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Gwenael Layec
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
- Institute for Applied Life Sciences, University of Massachusetts, Amherst, MA, USA
| | - Stephen J Ives
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA.
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