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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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Rosbrook P, Sweet D, Qiao J, Looney DP, Margolis LM, Hostler D, Pryor RR, Pryor JL. Heat stress increases carbohydrate oxidation rates and oxygen uptake during prolonged load carriage exercise. Temperature (Austin) 2024; 11:170-181. [PMID: 38846526 PMCID: PMC11152092 DOI: 10.1080/23328940.2024.2322920] [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: 08/17/2023] [Accepted: 02/19/2024] [Indexed: 06/09/2024] Open
Abstract
Military missions are conducted in a multitude of environments including heat and may involve walking under load following severe exertion, the metabolic demands of which may have nutritional implications for fueling and recovery planning. Ten males equipped a military pack loaded to 30% of their body mass and walked in 20°C/40% relative humidity (RH) (TEMP) or 37°C/20% RH (HOT) either continuously (CW) for 90 min at the first ventilatory threshold or mixed walking (MW) with unloaded running intervals above the second ventilatory threshold between min 35 and 55 of the 90 min bout. Pulmonary gas, thermoregulatory, and cardiovascular variables were analyzed following running intervals. Final rectal temperature (MW: p < 0.001, g = 3.81, CW: p < 0.001, g = 4.04), oxygen uptake, cardiovascular strain, and energy expenditure were higher during HOT trials (p ≤ 0.05) regardless of exercise type. Both HOT trials elicited higher final carbohydrate oxidation (CHOox) than TEMP CW at min 90 (HOT MW: p < 0.001, g = 1.45, HOT CW: p = 0.009, g = 0.67) and HOT MW CHOox exceeded TEMP MW at min 80 and 90 (p = 0.049, g = 0.60 and p = 0.024, g = 0.73, respectively). There were no within-environment differences in substrate oxidation indicating that severe exertion work cycles did not produce a carryover effect during subsequent loaded walking. The rate of CHOox during 90 minutes of load carriage in the heat appears to be primarily affected by accumulated thermal load.
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Affiliation(s)
- Paul Rosbrook
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - Daniel Sweet
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - JianBo Qiao
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - David P. Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, USA
| | - Lee M. Margolis
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, USA
| | - David Hostler
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - Riana R. Pryor
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - J. Luke Pryor
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
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Tan XR, Stephenson MC, Alhadad SB, Loh KWZ, Soong TW, Lee JKW, Low ICC. Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function. JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 13:233-244. [PMID: 37678507 PMCID: PMC10980903 DOI: 10.1016/j.jshs.2023.09.001] [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: 03/01/2023] [Revised: 05/27/2023] [Accepted: 07/20/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Excessive heat exposure can lead to hyperthermia in humans, which impairs physical performance and disrupts cognitive function. While heat is a known physiological stressor, it is unclear how severe heat stress affects brain physiology and function. METHODS Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures (Tre) attained 39.5°C, inducing exertional or passive hyperthermia, respectively. In a separate trial, blended ice was ingested before and during exercise as a cooling strategy. Data were compared to a control condition with seated rest (normothermic). Brain temperature (Tbr), cerebral perfusion, and task-based brain activity were assessed using magnetic resonance imaging techniques. RESULTS Tbr in motor cortex was found to be tightly regulated at rest (37.3°C ± 0.4°C (mean ± SD)) despite fluctuations in Tre. With the development of hyperthermia, Tbr increases and dovetails with the rising Tre. Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks, implying a reduced central motor drive in hyperthermic participants (Tre = 38.5°C ± 0.1°C). Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive hyperthermia. Executive function was poorer under a passive hyperthermic state, and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital cortex. Conversely, ingestion of blended ice before and during exercise alleviated the rise in both Tre and Tbr and mitigated heat-related neural perturbations. CONCLUSION Severe heat exposure elevates Tbr, disrupts motor cortical activity and executive function, and this can lead to impairment of physical and cognitive performance.
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Affiliation(s)
- Xiang Ren Tan
- Health and Social Sciences, Singapore Institute of Technology, Singapore 138683, Singapore; Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Mary C Stephenson
- Centre for Translational Magnetic Resonance Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore
| | - Sharifah Badriyah Alhadad
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Kelvin W Z Loh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Jason K W Lee
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117510, Singapore; N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore; Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore.
| | - Ivan C C Low
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
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Eifling KP, Gaudio FG, Dumke C, Lipman GS, Otten EM, Martin AD, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update. Wilderness Environ Med 2024; 35:112S-127S. [PMID: 38425235 DOI: 10.1177/10806032241227924] [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: 03/02/2024]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.
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Affiliation(s)
- Kurt P Eifling
- Department of Emergency Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Flavio G Gaudio
- Department of Emergency Medicine, New York-Presbyterian Hospital / Weill Cornell Medical College, New York, NY
| | - Charles Dumke
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, MT
| | | | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH
| | - August D Martin
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT
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Laguarta-Val S, Varillas-Delgado D, Lizcano-Álvarez Á, Molero-Sánchez A, Melian-Ortiz A, Cano-de-la-Cuerda R, Jiménez-Antona C. Effects of Aerobic Exercise Therapy through Nordic Walking Program in Lactate Concentrations, Fatigue and Quality-of-Life in Patients with Long-COVID Syndrome: A Non-Randomized Parallel Controlled Trial. J Clin Med 2024; 13:1035. [PMID: 38398348 PMCID: PMC10889227 DOI: 10.3390/jcm13041035] [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: 01/23/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Long-COVID syndrome comprises a variety of signs and symptoms that develop during or after infection with COVID-19 which may affect the physical capabilities. However, there is a lack of studies investigating the effects of Long-COVID syndrome in sport capabilities after suffering from COVID-19 infection. The purpose of the study was to evaluate and compare lactate concentration and quality of life (QoL) in patients with Long-COVID with those who have not developed non-Long-COVID during Nordic walking exercise therapy. METHODS Twenty-nine patients (25.5 ± 7.1 years) took part in a non-randomized controlled trial, divided into two groups: a Long-COVID group (n = 16) and a non-Long-COVID control (n = 13). Patients were confirmed as having Long-COVID syndrome if they experienced fatigue or tiredness when performing daily activities and worsening of symptoms after vigorous physical or mental activity. All participants underwent a 12-week Nordic Walking program. Lactate concentration after exercise and distance covered during all sessions were measured. Pre- and Long-Nordic Walking program, the Modified Fatigue Impact Scale (MFIS), the Short Form 36 Health Survey (SF-36), and EURO QoL-5D (EQ-ED) were administered to assess fatigue and quality of life, respectively. RESULTS There was a lactate concentration effect between groups (F = 5.604; p = 0.024). However, there was no significant effect as a result of the session (F = 3.521; p = 0.121) with no interaction of group × session (F = 1.345; p = 0.414). The group main effect (F = 23.088; p < 0.001), time effect (F = 6.625; p = 0.026), and group × time (F = 4.632; p = 0.002) interaction on the SF-36 scale were noted. Also, there were a significant group main effect (F = 38.372; p < 0.001), time effect (F = 12.424; p = 0.005), and group × time interaction (F = 4.340; p = 0.014) on EQ-5D. However, there was only a significant group main effect (F = 26.235; p < 0.001) with no effect on time (F = 2.265; p = 0.160) and group × time (F = 1.584; p = 0.234) interaction on the MFIS scale. CONCLUSIONS The Long-COVID group showed higher lactate concentration compared with the control group during the 12 weeks of the Nordic Walking program. The Long-COVID group presented a decrease in fatigue with respect to the control group according to the MFIS scale, as well as improvement in quality of life after aerobic exercise therapy.
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Affiliation(s)
- Sofía Laguarta-Val
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Faculty of Health Sciences, Universidad Rey Juan Carlos, Alcorcon, 28922 Madrid, Spain; (S.L.-V.); (A.M.-S.); (R.C.-d.-l.-C.); (C.J.-A.)
| | - David Varillas-Delgado
- Department of Exercise and Sport Science, Faculty of Health Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo, Spain
| | - Ángel Lizcano-Álvarez
- Department of Nursing and Stomatology, Faculty of Health Sciences, Universidad Rey Juan Carlos, Alcorcon, 28922 Madrid, Spain;
| | - Alberto Molero-Sánchez
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Faculty of Health Sciences, Universidad Rey Juan Carlos, Alcorcon, 28922 Madrid, Spain; (S.L.-V.); (A.M.-S.); (R.C.-d.-l.-C.); (C.J.-A.)
| | - Alberto Melian-Ortiz
- Faculty of Nursing and Physiotherapy, Universidad Pontificia de Salamanca, 28015 Madrid, Spain;
| | - Roberto Cano-de-la-Cuerda
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Faculty of Health Sciences, Universidad Rey Juan Carlos, Alcorcon, 28922 Madrid, Spain; (S.L.-V.); (A.M.-S.); (R.C.-d.-l.-C.); (C.J.-A.)
| | - Carmen Jiménez-Antona
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Faculty of Health Sciences, Universidad Rey Juan Carlos, Alcorcon, 28922 Madrid, Spain; (S.L.-V.); (A.M.-S.); (R.C.-d.-l.-C.); (C.J.-A.)
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise. Eur J Appl Physiol 2024; 124:1-145. [PMID: 37796292 DOI: 10.1007/s00421-023-05276-3] [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: 01/26/2023] [Accepted: 07/04/2023] [Indexed: 10/06/2023]
Abstract
In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.
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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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Blazevich AJ, Fletcher JR. More than energy cost: multiple benefits of the long Achilles tendon in human walking and running. Biol Rev Camb Philos Soc 2023; 98:2210-2225. [PMID: 37525526 DOI: 10.1111/brv.13002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 08/02/2023]
Abstract
Elastic strain energy that is stored and released from long, distal tendons such as the Achilles during locomotion allows for muscle power amplification as well as for reduction of the locomotor energy cost: as distal tendons perform mechanical work during recoil, plantar flexor muscle fibres can work over smaller length ranges, at slower shortening speeds, and at lower activation levels. Scant evidence exists that long distal tendons evolved in humans (or were retained from our more distant Hominoidea ancestors) primarily to allow high muscle-tendon power outputs, and indeed we remain relatively powerless compared to many other species. Instead, the majority of evidence suggests that such tendons evolved to reduce total locomotor energy cost. However, numerous additional, often unrecognised, advantages of long tendons may speculatively be of greater evolutionary advantage, including the reduced limb inertia afforded by shorter and lighter muscles (reducing proximal muscle force requirement), reduced energy dissipation during the foot-ground collisions, capacity to store and reuse the muscle work done to dampen the vibrations triggered by foot-ground collisions, reduced muscle heat production (and thus core temperature), and attenuation of work-induced muscle damage. Cumulatively, these effects should reduce both neuromotor fatigue and sense of locomotor effort, allowing humans to choose to move at faster speeds for longer. As these benefits are greater at faster locomotor speeds, they are consistent with the hypothesis that running gaits used by our ancestors may have exerted substantial evolutionary pressure on Achilles tendon length. The long Achilles tendon may therefore be a singular adaptation that provided numerous physiological, biomechanical, and psychological benefits and thus influenced behaviour across multiple tasks, both including and additional to locomotion. While energy cost may be a variable of interest in locomotor studies, future research should consider the broader range of factors influencing our movement capacity, including our decision to move over given distances at specific speeds, in order to understand more fully the effects of Achilles tendon function as well as changes in this function in response to physical activity, inactivity, disuse and disease, on movement performance.
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Affiliation(s)
- Anthony J Blazevich
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, Western Australia, Australia
| | - Jared R Fletcher
- Department of Health and Physical Education, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, Alberta, Canada
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López-Torres O, Rodríguez-Longobardo C, Escribano-Tabernero R, Fernández-Elías VE. Hydration, Hyperthermia, Glycogen, and Recovery: Crucial Factors in Exercise Performance-A Systematic Review and Meta-Analysis. Nutrients 2023; 15:4442. [PMID: 37892517 PMCID: PMC10610078 DOI: 10.3390/nu15204442] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Hyperthermia accelerates dehydration and can lead to a glycolysis malfunction. Therefore, to deeply understand the relationship between dehydration and hyperthermia during exercise, as well as in the recovery time, there might be important factors to improve athletic performance. A systematic review was carried out in different databases using the words "hydration" OR "dehydration" AND "glycogen" OR "glycogenesis" OR "glycogenolysis" AND "muscle" OR "muscle metabolism" OR "cardiovascular system" and adding them to the "topic section" in Web of Science, to "Title/Abstract" in PubMed and to "Abstract" in SPORTDiscus. A total of 18 studies were included in the review and 13 in the meta-analysis. The free statistical software Jamovi was used to run the meta-analysis (version 1.6.15). A total sample of 158 people was included in the qualitative analysis, with a mean age of 23.5 years. Ten studies compared muscle glycogen content after hydration vs. remaining dehydrated (SMD -4.77 to 3.71, positive 80% of estimates, \hat{\mu} = 0.79 (95% CI: -0.54 to 2.12), z = 1.17, p = 0.24, Q-test (Q(9) = 66.38, p < 0.0001, tau2 = 4.14, I2 = 91.88%). Four studies examined the effect of temperature on postexercise muscle glycogen content (SMD -3.14 to -0.63, 100% of estimates being negative, \hat{\mu} = -1.52 (95% CI: -2.52 to -0.53), (z = -3.00, p = 0.003, Q-test (Q(3) = 8.40, p = 0.038, tau2 = 0.68, I2 = 66.81%). In conclusion, both hyperthermia and dehydration may contribute to elevated glycogenolysis during exercise and poor glycogen resynthesis during recovery. Although core and muscle hyperthermia are the key factors in glycogen impairments, they are also directly related to dehydration.
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Affiliation(s)
- Olga López-Torres
- Sports Department, Faculty of Physical Activity and Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain; (R.E.-T.); (V.E.F.-E.)
| | - Celia Rodríguez-Longobardo
- Social Sciences of Physical Activity, Sport and Leisure Department, Faculty of Physical Activity and Sport Sciences, Universidad Politécnica de Madrid, 28040 Madrid, Spain;
| | - Rodrigo Escribano-Tabernero
- Sports Department, Faculty of Physical Activity and Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain; (R.E.-T.); (V.E.F.-E.)
| | - Valentín E. Fernández-Elías
- Sports Department, Faculty of Physical Activity and Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain; (R.E.-T.); (V.E.F.-E.)
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Charoensap T, Kilding AE, Maunder E. Carbohydrate, but not fat, oxidation is reduced during moderate-intensity exercise performed in 33 vs. 18 °C at matched heart rates. Eur J Appl Physiol 2023; 123:2073-2085. [PMID: 37199760 PMCID: PMC10193330 DOI: 10.1007/s00421-023-05225-0] [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: 12/12/2022] [Accepted: 05/06/2023] [Indexed: 05/19/2023]
Abstract
PURPOSE Exposure to environmental heat stress increases carbohydrate oxidation and extracellular heat shock protein 70 (HSP70) concentrations during endurance exercise at matched absolute, external work rates. However, a reduction in absolute work rate typically occurs when unacclimated endurance athletes train and/or compete in hot environments. We sought to determine the effect of environmental heat stress on carbohydrate oxidation rates and plasma HSP70 expression during exercise at matched heart rates (HR). METHODS Ten endurance-trained, male cyclists performed two experimental trials in an acute, randomised, counterbalanced cross-over design. Each trial involved a 90-min bout of cycling exercise at 95% of the HR associated with the first ventilatory threshold in either 18 (TEMP) or 33 °C (HEAT), with ~ 60% relative humidity. RESULTS Mean power output (17 ± 11%, P < 0.001) and whole-body energy expenditure (14 ± 8%, P < 0.001) were significantly lower in HEAT. Whole-body carbohydrate oxidation rates were significantly lower in HEAT (19 ± 11%, P = 0.002), while fat oxidation rates were not different between-trials. The heat stress-induced reduction in carbohydrate oxidation was associated with the observed reduction in power output (r = 0.64, 95% CI, 0.01, 0.91, P = 0.05) and augmented sweat rates (r = 0.85, 95% CI, 0.49, 0.96, P = 0.002). Plasma HSP70 and adrenaline concentrations were not increased with exercise in either environment. CONCLUSION These data contribute to our understanding of how moderate environmental heat stress is likely to influence substrate oxidation and plasma HSP70 expression in an ecologically-valid model of endurance exercise.
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Affiliation(s)
- Thanchanok Charoensap
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Ed Maunder
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand.
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10
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González‐Alonso J, Calbet JAL, Mora‐Rodríguez R, Kippelen P. Pulmonary ventilation and gas exchange during prolonged exercise in humans: Influence of dehydration, hyperthermia and sympathoadrenal activity. Exp Physiol 2023; 108:188-206. [PMID: 36622358 PMCID: PMC10103888 DOI: 10.1113/ep090909] [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: 10/15/2022] [Accepted: 11/30/2022] [Indexed: 01/10/2023]
Abstract
NEW FINDINGS What is the central question of the study? Ventilation increases during prolonged intense exercise, but the impact of dehydration and hyperthermia, with associated blunting of pulmonary circulation, and independent influences of dehydration, hyperthermia and sympathoadrenal discharge on ventilatory and pulmonary gas exchange responses remain unclear. What is the main finding and its importance? Dehydration and hyperthermia led to hyperventilation and compensatory adjustments in pulmonary CO2 and O2 exchange, such that CO2 output increased and O2 uptake remained unchanged despite the blunted circulation. Isolated hyperthermia and adrenaline infusion, but not isolated dehydration, increased ventilation to levels similar to combined dehydration and hyperthermia. Hyperthermia is the main stimulus increasing ventilation during prolonged intense exercise, partly via sympathoadrenal activation. ABSTRACT The mechanisms driving hyperthermic hyperventilation during exercise are unclear. In a series of retrospective analyses, we evaluated the impact of combined versus isolated dehydration and hyperthermia and the effects of sympathoadrenal discharge on ventilation and pulmonary gas exchange during prolonged intense exercise. In the first study, endurance-trained males performed two submaximal cycling exercise trials in the heat. On day 1, participants cycled until volitional exhaustion (135 ± 11 min) while experiencing progressive dehydration and hyperthermia. On day 2, participants maintained euhydration and core temperature (Tc ) during a time-matched exercise (control). At rest and during the first 20 min of exercise, pulmonary ventilation (V ̇ E ${\skew2\dot V_{\rm{E}}}$ ), arterial blood gases, CO2 output and O2 uptake were similar in both trials. At 135 ± 11 min, however,V ̇ E ${\skew2\dot V_{\rm{E}}}$ was elevated with dehydration and hyperthermia, and this was accompanied by lower arterial partial pressure of CO2 , higher breathing frequency, arterial partial pressure of O2 , arteriovenous CO2 and O2 differences, and elevated CO2 output and unchanged O2 uptake despite a reduced pulmonary circulation. The increasedV ̇ E ${\skew2\dot V_{\rm{E}}}$ was closely related to the rise in Tc and circulating catecholamines (R2 ≥ 0.818, P ≤ 0.034). In three additional studies in different participants, hyperthermia independently increasedV ̇ E ${\skew2\dot V_{\rm{E}}}$ to an extent similar to combined dehydration and hyperthermia, whereas prevention of hyperthermia in dehydrated individuals restoredV ̇ E ${\skew2\dot V_{\rm{E}}}$ to control levels. Furthermore, adrenaline infusion during exercise elevated both Tc andV ̇ E ${\skew2\dot V_{\rm{E}}}$ . These findings indicate that: (1) adjustments in pulmonary gas exchange limit homeostatic disturbances in the face of a blunted pulmonary circulation; (2) hyperthermia is the main stimulus increasing ventilation during prolonged intense exercise; and (3) sympathoadrenal activation might partly mediate the hyperthermic hyperventilation.
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Affiliation(s)
- José González‐Alonso
- Division of SportHealth and Exercise SciencesDepartment of Life SciencesBrunel University LondonUxbridgeUK
| | - José A. L. Calbet
- Department of Physical Education & Research Institute for Biomedical and Health Sciences (IUIBS)University of Las Palmas de Gran CanariaGran CanariaSpain
- Department of Physical PerformanceNorwegian School of Sport SciencesOsloNorway
| | - Ricardo Mora‐Rodríguez
- Department of Physical Activity and Sport SciencesUniversity of Castilla‐La ManchaToledoSpain
| | - Pascale Kippelen
- Division of SportHealth and Exercise SciencesDepartment of Life SciencesBrunel University LondonUxbridgeUK
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11
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Racinais S, Hosokawa Y, Akama T, Bermon S, Bigard X, Casa DJ, Grundstein A, Jay O, Massey A, Migliorini S, Mountjoy M, Nikolic N, Pitsiladis YP, Schobersberger W, Steinacker JM, Yamasawa F, Zideman DA, Engebretsen L, Budgett R. IOC consensus statement on recommendations and regulations for sport events in the heat. Br J Sports Med 2023; 57:8-25. [PMID: 36150754 PMCID: PMC9811094 DOI: 10.1136/bjsports-2022-105942] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2022] [Indexed: 01/07/2023]
Abstract
This document presents the recommendations developed by the IOC Medical and Scientific Commission and several international federations (IF) on the protection of athletes competing in the heat. It is based on a working group, meetings, field experience and a Delphi process. The first section presents recommendations for event organisers to monitor environmental conditions before and during an event; to provide sufficient ice, shading and cooling; and to work with the IF to remove regulatory and logistical limitations. The second section summarises recommendations that are directly associated with athletes' behaviours, which include the role and methods for heat acclimation; the management of hydration; and adaptation to the warm-up and clothing. The third section explains the specific medical management of exertional heat stroke (EHS) from the field of play triage to the prehospital management in a dedicated heat deck, complementing the usual medical services. The fourth section provides an example for developing an environmental heat risk analysis for sport competitions across all IFs. In summary, while EHS is one of the leading life-threatening conditions for athletes, it is preventable and treatable with the proper risk mitigation and medical response. The protection of athletes competing in the heat involves the close cooperation of the local organising committee, the national and international federations, the athletes and their entourages and the medical team.
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Affiliation(s)
- Sebastien Racinais
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Ad Dawhah, Qatar
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Takao Akama
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | | | - Xavier Bigard
- Union Cycliste Internationale (UCI), Aigle, Switzerland
| | - Douglas J Casa
- Korey Stringer Institiute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA
| | - Andrew Grundstein
- Department of Geography, University of Georgia, Athens, Georgia, USA
| | - Ollie Jay
- Heat and Health Research Incubator, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
| | - Andrew Massey
- Medical Department, Federation Internationale de Football Association, Zurich, Switzerland
| | | | | | | | | | - Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine & Health Tourism (ISAG), UMIT Tirol – Private University for Health Sciences and technology, Hall, Austria,University Hospital/Tirol Kliniken, Innsbruck, Austria
| | | | | | - David Anthony Zideman
- International Olympic Committee Medical and Scientific Games Group, Pinner, Middlesex, UK
| | - Lars Engebretsen
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
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12
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Stöhr EJ. The healthy heart does not control a specific cardiac output: a plea for a new interpretation of normal cardiac function. Am J Physiol Heart Circ Physiol 2022; 323:H1239-H1243. [PMID: 36269649 DOI: 10.1152/ajpheart.00535.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The current evidence suggests that the healthy heart does not sense the optimal cardiac output (Q̇) because the different organ systems that influence cardiac function do not interact to adjust their individual responses toward a specific Q̇. Consequently, it is conceivable that the complex cycle of cardiac contraction and relaxation must occur for reasons other than to produce a specific target Q̇ and that there is likely a yet undiscovered overarching principle in the cardiovascular system that explains the combined effects of the prevailing preload, afterload, and contractility. Future research should embrace the possibility of a different purpose to cardiac function than previously assumed and examine the biological capacity of this fascinating organ accordingly.
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Affiliation(s)
- Eric J Stöhr
- COR-HELIX (CardiOvascular Regulation and Human Exercise Laboratory - Integration and Xploration), Leibniz University Hannover, Hannover, Germany
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13
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Ravindra PV, Janhavi P, Divyashree S, Muthukumar SP. Nutritional interventions for improving the endurance performance in athletes. Arch Physiol Biochem 2022; 128:851-858. [PMID: 32223574 DOI: 10.1080/13813455.2020.1733025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Endurance refers to the ability of skeletal muscles to perform continuously withstanding the hardships of exercise. Endurance exercises have three phases: pre-, during-, and post-workout phase. The nutritional requirements that drive these phases vary on intensity, type of workout, individual's body composition, training, weather conditions, etc. Generally, the pre-workout phase requires glycogen synthesis and spare glycogen breakdown. While workout phase, requires rapid absorption of exogenous glucose, insulin release to transport glucose into muscle cells, replenish the loss of electrolytes, promote fluid retention, etc. However, post-workout phase requires quick amino acid absorption, muscle protein synthesis, repair of damaged muscle fibres and tendon, ameliorate inflammation, oxidative stress, etc. Therefore, nutritional sources that can help these metabolic requirements is recommended. In this review, various dietary interventions including timing and amount of nutrient consumption that can promote the above metabolic requirements that in turn support in improving the endurance potential in athletes are discussed.HIGHLIGHTSReview article describes nutritional requirements of endurance exercises.It also describes nutritional interventions to enhance the endurance potential in athletes.
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Affiliation(s)
- P V Ravindra
- Department of Biochemistry, CSIR-CFTRI, Mysuru, India
| | - P Janhavi
- Department of Biochemistry, CSIR-CFTRI, Mysuru, India
| | - S Divyashree
- Department of Biochemistry, CSIR-CFTRI, Mysuru, India
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14
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Wang J, Guan H, Hostrup M, Rowlands DS, González-Alonso J, Jensen J. The Road to the Beijing Winter Olympics and Beyond: Opinions and Perspectives on Physiology and Innovation in Winter Sport. JOURNAL OF SCIENCE IN SPORT AND EXERCISE 2021; 3:321-331. [PMID: 36304069 PMCID: PMC8475427 DOI: 10.1007/s42978-021-00133-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/24/2021] [Indexed: 11/28/2022]
Abstract
Beijing will host the 2022 Winter Olympics, and China strengthens research on various aspects to allow their athletes to compete successfully in winter sport. Simultaneously, Government-directed initiatives aim to increase public participation in recreational winter sport. These parallel developments allow research to advance knowledge and understanding of the physiological determinants of performance and health related to winter sport. Winter sport athletes often conduct a substantial amount of training with high volumes of low-to-moderate exercise intensity and lower volumes of high-intensity work. Moreover, much of the training occur at low ambient temperatures and winter sport athletes have high risk of developing asthma or asthma-related conditions, such as exercise-induced bronchoconstriction. The high training volumes require optimal nutrition with increased energy and dietary protein requirement to stimulate muscle protein synthesis response in the post-exercise period. Whether higher protein intake is required in the cold should be investigated. Cross-country skiing is performed mostly in Northern hemisphere with a strong cultural heritage and sporting tradition. It is expected that innovative initiatives on recruitment and training during the next few years will target to enhance performance of Chinese athletes in classical endurance-based winter sport. The innovation potential coupled with resourcing and population may be substantial with the potential for China to become a significant winter sport nation. This paper discusses the physiological aspects of endurance training and performance in winter sport highlighting areas where innovation may advance in athletic performance in cold environments. In addition, to ensure sustainable development of snow sport, a quality ski patrol and rescue system is recommended for the safety of increasing mass participation.
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Affiliation(s)
- Jun Wang
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Hongwei Guan
- Department of Health Promotion and Physical Education, School of Health Sciences and Human Performance, Ithaca College, Ithaca, NY 14850 USA
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - David S. Rowlands
- School of Sport, Exercise, and Nutrition, College of Health, Massey University, Auckland, New Zealand
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Jørgen Jensen
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
- Department of Physical Performance, Norwegian School of Sport Sciences, Ullevål Stadion, P.O.Box 4012, 0806 Oslo, Norway
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15
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Périard JD, Eijsvogels TMH, Daanen HAM. Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies. Physiol Rev 2021; 101:1873-1979. [PMID: 33829868 DOI: 10.1152/physrev.00038.2020] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.
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Affiliation(s)
- Julien D Périard
- University of Canberra Research Institute for Sport and Exercise, Bruce, Australia
| | - Thijs M H Eijsvogels
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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16
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Wiśniewski D, Śliwicka E, Malik J, Durkalec-Michalski K. Evaluation of Fluid Loss and Customary Fluid Intake among a Selected Group of Young Swimmers: A Preliminary Field Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18063205. [PMID: 33808826 PMCID: PMC8003718 DOI: 10.3390/ijerph18063205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/26/2022]
Abstract
This study aimed to assess fluid loss (FL) and customary fluid intake (FI) during a training session, and the relationship between FL and total body water (TBW) content in a selected group of young swimmers. The study involved 17 (seven females, 10 males) individuals whose anthropometric and body composition analyses and FI during training units were carried out. The total average FI and total actual FL oscillated around 531 mL and −513 mL for the whole study group (469 mL and −284 mL for females, 574 mL and −674 mL for males). The dependent and independent sample t-tests, the Cohen’s d effect size and Pearson’s correlation coefficient were analysed. Significant differences were observed between pre-workout and post-workout body weights after training without FI in the whole group (66.5 kg vs. 66.0 kg, p < 0.001, d = 0.06), in females (61.2 kg vs. 60.9 kg, p = 0.015, d = 0.04) and males (70.3 kg vs. 69.6 kg, p < 0.001, d = 0.9). For the TBW content and fat-free mass (FFM) before and after training, significant differences were observed only in males (TBW: 43.8 L vs. 43.2 L, p = 0.002, d = 0.14; and 62.4% vs. 61.7%, p < 0.001, d = 0.36; FFM: 59.8 kg vs. 59.1 kg, p = 0.002, d = 0.12). Moreover, the relationship between the actual FL and TBW before training was observed in the whole (mL vs. %: r = −0.64, p = 0.006; mL vs. L: r = −0.84, p < 0.001) and the male group (mL vs. L: r = −0.73, p = 0.017). These results indicated FL in young swimmers during training and the relationship between FL and pre-training TBW content, which suggests that it is important to also pay special attention to effective hydration procedures before and during training in aquatic environments.
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Affiliation(s)
- Damian Wiśniewski
- Department of Sports Dietetics, Poznan University of Physical Education, 61-871 Poznań, Poland;
| | - Ewa Śliwicka
- Department of Physiology and Biochemistry, Poznan University of Physical Education, 61-871 Poznań, Poland;
| | - Jakub Malik
- Department of Physical Activity and Health Promotion Science, Poznan University of Physical Education, 61-871 Poznań, Poland;
| | - Krzysztof Durkalec-Michalski
- Department of Sports Dietetics, Poznan University of Physical Education, 61-871 Poznań, Poland;
- Department of Human Nutrition and Dietetics, Poznan University of Life Sciences, 61-871 Poznań, Poland
- Correspondence: ; Tel.: +48-61-835-52-87
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17
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Abstract
Exercise in humans increases muscle glucose uptake up to 100-fold compared with rest. The magnitude of increase depends on exercise intensity and duration. Although knockout of glucose transporter type 4 (GLUT4) convincingly has shown that GLUT4 is necessary for exercise to increase muscle glucose uptake, studies only show an approximate twofold increase in GLUT4 translocation to the muscle cell membrane when transitioning from rest to exercise. Therefore, there is a big discrepancy between the increase in glucose uptake and GLUT4 translocation. It is suggested that either the methods for measurements of GLUT4 translocation in muscle grossly underestimate the real translocation of GLUT4 or, alternatively, GLUT4 intrinsic activity increases in muscle during exercise, perhaps due to increased muscle temperature and/or mechanical effects during contraction/relaxation cycles.
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Affiliation(s)
- Erik A Richter
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Denmark
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18
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Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab 2020; 2:817-828. [PMID: 32747792 DOI: 10.1038/s42255-020-0251-4] [Citation(s) in RCA: 411] [Impact Index Per Article: 102.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The continual supply of ATP to the fundamental cellular processes that underpin skeletal muscle contraction during exercise is essential for sports performance in events lasting seconds to several hours. Because the muscle stores of ATP are small, metabolic pathways must be activated to maintain the required rates of ATP resynthesis. These pathways include phosphocreatine and muscle glycogen breakdown, thus enabling substrate-level phosphorylation ('anaerobic') and oxidative phosphorylation by using reducing equivalents from carbohydrate and fat metabolism ('aerobic'). The relative contribution of these metabolic pathways is primarily determined by the intensity and duration of exercise. For most events at the Olympics, carbohydrate is the primary fuel for anaerobic and aerobic metabolism. Here, we provide an overview of exercise metabolism and the key regulatory mechanisms ensuring that ATP resynthesis is closely matched to the ATP demand of exercise. We also summarize various interventions that target muscle metabolism for ergogenic benefit in athletic events.
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Affiliation(s)
- Mark Hargreaves
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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19
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Zaplatosch ME, Adams WM. The Effect of Acute Hypohydration on Indicators of Glycemic Regulation, Appetite, Metabolism and Stress: A Systematic Review and Meta-Analysis. Nutrients 2020; 12:nu12092526. [PMID: 32825404 PMCID: PMC7551868 DOI: 10.3390/nu12092526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/09/2020] [Accepted: 08/18/2020] [Indexed: 12/22/2022] Open
Abstract
Evidence synthesizing the effects of acute body water losses on various markers of glycemic regulation, appetite, metabolism, and stress is lacking. Thus, the purpose of this review was to summarize the response of various hormonal changes involved in these physiologic functions to dehydration. A comprehensive literature search for peer-reviewed research in the databases PubMed, Scopus, CINAHL, and SportDiscus was conducted. Studies were included if they contained samples of adults (>18 years) and experimentally induced dehydration as measured by acute body mass loss. Twenty-one articles were eligible for inclusion. Findings suggested cortisol is significantly elevated with hypohydration (standard mean difference [SMD] = 1.12, 95% CI [0.583, 1.67], p < 0.0001). Testosterone was significantly lower in studies where hypohydration was accompanied by caloric restriction (SMD= -1.04, 95% CI [-1.93, -0.14], p = 0.02), however, there were no changes in testosterone in studies examining hypohydration alone (SMD = -0.17, 95% CI [-0.51 0.16], p = 0.30). Insulin and ghrelin were unaffected by acute total body water losses. Acute hypohydration increases markers of catabolism but has a negligible effect on markers of glycemic regulation, appetite, anabolism and stress. Given the brevity of existing research, further research is needed to determine the impact of hydration on glucagon, leptin, peptide YY and the subsequent outcomes relevant to both health and performance.
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20
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Watanabe K, Stöhr EJ, Akiyama K, Watanabe S, González‐Alonso J. Dehydration reduces stroke volume and cardiac output during exercise because of impaired cardiac filling and venous return, not left ventricular function. Physiol Rep 2020; 8:e14433. [PMID: 32538549 PMCID: PMC7294577 DOI: 10.14814/phy2.14433] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 12/17/2022] Open
Abstract
Dehydration accrued during intense prolonged whole-body exercise in the heat compromises peripheral blood flow and cardiac output ( Q ˙ ). A markedly reduced stroke volume (SV) is a key feature of the dehydration-induced cardiovascular strain, but whether the lower output of the heart is mediated by peripheral or cardiac factors remains unknown. Therefore, we repeatedly quantified left ventricular (LV) volumes, LV mechanics (LV twist, a marker of systolic muscle function, and LV untwisting rate, an independent marker of LV muscle relaxation), left intra-ventricular pressure gradients, blood volume and peripheral blood flow during 2 hr of cycling in the heat with and without dehydration (DEH: 4.0 ± 0.2% body mass loss and EUH: euhydration control, respectively) in eight participants (three females and five males). While brachial and carotid blood flow, blood volume, SV, LV end-diastolic volume (LVEDV), cardiac filling time, systemic vascular conductance and Q ˙ were reduced in DEH compared to EUH after 2 hr, LV twist and untwisting rate tended to be higher (p = .09 and .06, respectively) and intra-ventricular pressure gradients were not different between the two conditions (p = .22). Furthermore, LVEDV in DEH correlated strongly with blood volume (r = .995, p < .01), head and forearms beat volume (r = .98, p < .05), and diastolic LV filling time (r = .98, p < .05). These findings suggest that the decline in SV underpinning the blunted Q ˙ with exercise-induced dehydration is caused by compromised LV filling and venous return, but not intrinsic systolic or diastolic LV function.
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Affiliation(s)
- Kazuhito Watanabe
- Centre for Human Performance, Exercise and RehabilitationBrunel University LondonUxbridgeUK
- Faculty of Education and Human StudiesAkita UniversityAkitaJapan
| | - Eric J. Stöhr
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Department of MedicineDivision of CardiologyColumbia University Irving Medical CenterNew York CityNYUSA
| | - Koichi Akiyama
- Department of AnesthesiologyYodogawa Christian HospitalOsakaJapan
| | - Sumie Watanabe
- Centre for Human Performance, Exercise and RehabilitationBrunel University LondonUxbridgeUK
| | - José González‐Alonso
- Centre for Human Performance, Exercise and RehabilitationBrunel University LondonUxbridgeUK
- Division of Sport, Health and Exercise SciencesDepartment of Life SciencesBrunel University LondonUxbridgeUK
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21
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Sabou V, Rush C, Mason L, Dupont G, Louis J. Effects of training intensity and environmental condition on the hydration status of elite football players. SCI MED FOOTBALL 2020. [DOI: 10.1080/24733938.2020.1761558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Vlad Sabou
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Liverpool, UK
- Blackburn Rovers Football Club, Blackburn Rovers Football & Athletic Ltd, Blackburn, Lancashire, UK
| | - Chris Rush
- Blackburn Rovers Football Club, Blackburn Rovers Football & Athletic Ltd, Blackburn, Lancashire, UK
| | - Liam Mason
- Blackburn Rovers Football Club, Blackburn Rovers Football & Athletic Ltd, Blackburn, Lancashire, UK
| | - Grégory Dupont
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Liverpool, UK
| | - Julien Louis
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Liverpool, UK
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22
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Abstract
People undertaking prolonged vigorous exercise experience substantial bodily fluid losses due to thermoregulatory sweating. If these fluid losses are not replaced, endurance capacity may be impaired in association with a myriad of alterations in physiological function, including hyperthermia, hyperventilation, cardiovascular strain with reductions in brain, skeletal muscle and skin blood perfusion, greater reliance on muscle glycogen and cellular metabolism, alterations in neural activity and, in some conditions, compromised muscle metabolism and aerobic capacity. The physiological strain accompanying progressive exercise-induced dehydration to a level of ~ 4% of body mass loss can be attenuated or even prevented by: (1) ingesting fluids during exercise, (2) exercising in cold environments, and/or (3) working at intensities that require a small fraction of the overall body functional capacity. The impact of dehydration upon physiological function therefore depends on the functional demand evoked by exercise and environmental stress, as cardiac output, limb blood perfusion and muscle metabolism are stable or increase during small muscle mass exercise or resting conditions, but are impaired during whole-body moderate to intense exercise. Progressive dehydration is also associated with an accelerated drop in perfusion and oxygen supply to the human brain during submaximal and maximal endurance exercise. Yet their consequences on aerobic metabolism are greater in the exercising muscles because of the much smaller functional oxygen extraction reserve. This review describes how dehydration differentially impacts physiological function during exercise requiring low compared to high functional demand, with an emphasis on the responses of the human brain, heart and skeletal muscles.
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23
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Lipman GS, Gaudio FG, Eifling KP, Ellis MA, Otten EM, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update. Wilderness Environ Med 2019; 30:S33-S46. [DOI: 10.1016/j.wem.2018.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 10/26/2022]
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24
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Impact of Pre-exercise Hypohydration on Aerobic Exercise Performance, Peak Oxygen Consumption and Oxygen Consumption at Lactate Threshold: A Systematic Review with Meta-analysis. Sports Med 2019; 50:581-596. [DOI: 10.1007/s40279-019-01223-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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25
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Maunder E, Plews DJ, Merien F, Kilding AE. Exercise intensity regulates the effect of heat stress on substrate oxidation rates during exercise. Eur J Sport Sci 2019; 20:935-943. [PMID: 31566098 DOI: 10.1080/17461391.2019.1674928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Hyperthermia stimulates endogenous carbohydrate metabolism during exercise; however, it is not known if exercise intensity impacts the metabolic effect of heat stress. In the first study of this two-part investigation, endurance-trained male cyclists performed incremental exercise assessments in 18 and 35°C (60% rH). The stimulatory effect of heat stress on carbohydrate oxidation rates was greater at high vs. moderate vs. low relative intensity (P < 0.05). In agreement, no effects of heat stress on carbohydrate oxidation rates were observed during 60-min of subsequent low-intensity cycling. In study two, endurance-trained male cyclists performed 20-min of moderate-intensity (power at the first ventilatory threshold) and 5-min of high-intensity (power at the second ventilatory threshold) cycling in 18, 28, 34, and 40°C (60% rH). At moderate-intensity, carbohydrate oxidation rates were significantly elevated by heat stress in 40°C (P < 0.05), whereas at high-intensity carbohydrate oxidation rates were significantly elevated by heat stress in 34 and 40°C (P < 0.05). This exercise intensity-mediated regulation of the effect of heat stress on carbohydrate oxidation may be partially attributable to observed plasma adrenaline responses. Our data suggest that under moderate environmental heat stress (34-35°C, 60% rH), heat stress-induced changes in CHO oxidation rates are unlikely to occur unless the relative exercise intensity is high (81 ± 8%⩒O2max), whereas under more extreme environmental heat stress (40°C, 60% rH), these changes occur at lower relative intensities (69 ± 8%⩒O2max). This provides indication of when heat stress-induced metabolic changes during exercise are likely to occur.
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Affiliation(s)
- E Maunder
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
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26
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Obi S, Nakajima T, Hasegawa T, Nakamura F, Sakuma M, Toyoda S, Tei C, Inoue T. Heat induces myogenic transcription factors of myoblast cells via transient receptor potential vanilloid 1 (Trpv1). FEBS Open Bio 2018; 9:101-113. [PMID: 30652078 PMCID: PMC6325605 DOI: 10.1002/2211-5463.12550] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 09/25/2018] [Accepted: 10/30/2018] [Indexed: 12/17/2022] Open
Abstract
Exercise generates heat, blood flow, and metabolic changes, thereby inducing hypertrophy of skeletal muscle cells. However, the mechanism by which heat incudes hypertrophy in response to heat is not well known. Here, we hypothesized that heat would induce differentiation of myoblast cells. We investigated the underlying mechanism by which myoblast cells respond to heat. When mouse myoblast cells were exposed to 42 °C for over 30 min, the phosphorylation level of protein kinase C (PKC) and heat shock factor 1 (Hsf1) increased, and the mRNA and protein expression level of heat shock protein 70 (Hsp70) increased. Inhibitors of transient receptor potential vanilloid 1 (Trpv1), calmodulin, PKC, and Hsf1, and the small interfering RNA‐mediated knockdown of Trpv1 diminished those heat responses. Heat exposure increased the phosphorylation levels of thymoma viral proto‐oncogene 1 (Akt), mammalian target of rapamycin (mTOR), eukaryotic translation initiation factor 4E binding protein 1 (Eif4ebp1), and ribosomal protein S6 kinase, polypeptide 1 (S6K1). The knockdown of Trpv1 decreased these heat‐induced responses. Antagonists of Hsp70 inhibited the phosphorylation level of Akt. Finally, heat increased the protein expression level of skeletal muscle markers such as myocyte enhancer factor 2D, myogenic factor 5, myogenic factor 6, and myogenic differentiation 1. Heat also increased myotube formation. Knockdown of Trpv1 diminished heat‐induced increases of those proteins and myotube formation. These results indicate that heat induces myogenic transcription factors of myoblast cells through the Trpv1, calmodulin, PKC, Hsf1, Hsp70, Akt, mTOR, Eif4ebp1, and S6K1 pathway. Moreover, heat increases myotube formation through Trpv1.
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Affiliation(s)
- Syotaro Obi
- Research Support Center Dokkyo Medical University Tochigi Japan.,Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan
| | - Toshiaki Nakajima
- Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan.,Heart Center Dokkyo Medical University Hospital Tochigi Japan
| | - Takaaki Hasegawa
- Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan
| | - Fumitaka Nakamura
- Third Department of Internal Medicine Teikyo University Chiba Medical Center Japan
| | - Masashi Sakuma
- Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan
| | - Shigeru Toyoda
- Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan.,Heart Center Dokkyo Medical University Hospital Tochigi Japan
| | - Chuwa Tei
- Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan
| | - Teruo Inoue
- Research Support Center Dokkyo Medical University Tochigi Japan.,Department of Cardiovascular Medicine Dokkyo Medical University Tochigi Japan.,Heart Center Dokkyo Medical University Hospital Tochigi Japan
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27
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Gibson OR, Taylor L, Watt PW, Maxwell NS. Cross-Adaptation: Heat and Cold Adaptation to Improve Physiological and Cellular Responses to Hypoxia. Sports Med 2018; 47:1751-1768. [PMID: 28389828 PMCID: PMC5554481 DOI: 10.1007/s40279-017-0717-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To prepare for extremes of heat, cold or low partial pressures of oxygen (O2), humans can undertake a period of acclimation or acclimatization to induce environment-specific adaptations, e.g. heat acclimation (HA), cold acclimation (CA), or altitude training. While these strategies are effective, they are not always feasible due to logistical impracticalities. Cross-adaptation is a term used to describe the phenomenon whereby alternative environmental interventions, e.g. HA or CA, may be a beneficial alternative to altitude interventions, providing physiological stress and inducing adaptations observable at altitude. HA can attenuate physiological strain at rest and during moderate-intensity exercise at altitude via adaptations allied to improved O2 delivery to metabolically active tissue, likely following increases in plasma volume and reductions in body temperature. CA appears to improve physiological responses to altitude by attenuating the autonomic response to altitude. While no cross-acclimation-derived exercise performance/capacity data have been measured following CA, post-HA improvements in performance underpinned by aerobic metabolism, and therefore dependent on O2 delivery at altitude, are likely. At a cellular level, heat shock protein responses to altitude are attenuated by prior HA, suggesting that an attenuation of the cellular stress response and therefore a reduced disruption to homeostasis at altitude has occurred. This process is known as cross-tolerance. The effects of CA on markers of cross-tolerance is an area requiring further investigation. Because much of the evidence relating to cross-adaptation to altitude has examined the benefits at moderate to high altitudes, future research examining responses at lower altitudes should be conducted, given that these environments are more frequently visited by athletes and workers. Mechanistic work to identify the specific physiological and cellular pathways responsible for cross-adaptation between heat and altitude, and between cold and altitude, is warranted, as is exploration of benefits across different populations and physical activity profiles.
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Affiliation(s)
- Oliver R Gibson
- Centre for Human Performance, Exercise and Rehabilitation (CHPER), Brunel University London, Uxbridge, UK. .,Welkin Human Performance Laboratories, Centre for Sport and Exercise Science and Medicine (SESAME), University of Brighton, Denton Road, Eastbourne, UK.
| | - Lee Taylor
- Athlete Health and Performance Research Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Peter W Watt
- Welkin Human Performance Laboratories, Centre for Sport and Exercise Science and Medicine (SESAME), University of Brighton, Denton Road, Eastbourne, UK
| | - Neil S Maxwell
- Welkin Human Performance Laboratories, Centre for Sport and Exercise Science and Medicine (SESAME), University of Brighton, Denton Road, Eastbourne, UK
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28
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Zhao L, McMillan RP, Xie G, Giridhar SGLW, Baumgard LH, El-Kadi S, Selsby J, Ross J, Gabler N, Hulver MW, Rhoads RP. Heat stress decreases metabolic flexibility in skeletal muscle of growing pigs. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1096-R1106. [PMID: 30256682 DOI: 10.1152/ajpregu.00404.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Heat-stressed pigs experience metabolic alterations, including altered insulin profiles, reduced lipid mobilization, and compromised intestinal integrity. This is bioenergetically distinct from thermal neutral pigs on a similar nutritional plane. To delineate differences in substrate preferences between direct and indirect (via reduced feed intake) heat stress effects, skeletal muscle fuel metabolism was assessed. Pigs (35.3 ± 0.8 kg) were randomly assigned to three treatments: thermal neutral fed ad libitum (TN; 21°C, n = 8), heat stress fed ad libitum (HS; 35°C, n = 8), and TN, pair-fed/HS intake (PF; n = 8) for 7 days. Body temperature (TB) and feed intake (FI) were recorded daily. Longissimus dorsi muscle was biopsied for metabolic assays on days -2, 3, and 7 relative to initiation of environmental treatments. Heat stress increased TB and decreased FI ( P < 0.05). Heat stress inhibited incomplete fatty acid oxidation and glucose oxidation ( P < 0.05). Metabolic flexibility decreased in HS pigs compared with TN and PF controls ( P < 0.05). Both phosphofructokinase and pyruvate dehydrogenase (PDH) activities increased in PF ( P < 0.05); however, TN and HS did not differ. Heat stress inhibited citrate synthase and β-hydroxyacyl-CoA dehydrogenase (β-HAD) activities ( P < 0.05). Heat stress did not alter PDH phosphorylation or carnitine palmitoyltransferase 1 abundance but reduced acetyl-CoA carboxylase 1 (ACC1) protein abundance ( P < 0.05). In conclusion, HS decreased skeletal muscle fatty acid oxidation and metabolic flexibility, likely involving β-HAD and ACC regulation.
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Affiliation(s)
- Lidan Zhao
- Department of Animal and Poultry Sciences, Virginia Tech University , Blacksburg, Virginia
| | - Ryan P McMillan
- Virginia Tech Metabolic Phenotyping Core, Virginia Tech University , Blacksburg, Virginia
| | - Guohao Xie
- Department of Animal and Poultry Sciences, Virginia Tech University , Blacksburg, Virginia
| | | | - Lance H Baumgard
- Department of Animal Science, Iowa State University , Ames, Iowa
| | - Samer El-Kadi
- Department of Animal and Poultry Sciences, Virginia Tech University , Blacksburg, Virginia
| | - Joshua Selsby
- Department of Animal Science, Iowa State University , Ames, Iowa
| | - Jason Ross
- Department of Animal Science, Iowa State University , Ames, Iowa
| | - Nicholas Gabler
- Department of Animal Science, Iowa State University , Ames, Iowa
| | - Matthew W Hulver
- Virginia Tech Metabolic Phenotyping Core, Virginia Tech University , Blacksburg, Virginia.,Department of Human Nutrition, Foods and Exercise, Virginia Tech University , Blacksburg, Virginia
| | - Robert P Rhoads
- Department of Animal and Poultry Sciences, Virginia Tech University , Blacksburg, Virginia
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29
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Trangmar SJ, Chiesa ST, Kalsi KK, Secher NH, González-Alonso J. Whole body hyperthermia, but not skin hyperthermia, accelerates brain and locomotor limb circulatory strain and impairs exercise capacity in humans. Physiol Rep 2017; 5:5/2/e13108. [PMID: 28108645 PMCID: PMC5269410 DOI: 10.14814/phy2.13108] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 12/26/2022] Open
Abstract
Cardiovascular strain and hyperthermia are thought to be important factors limiting exercise capacity in heat‐stressed humans, however, the contribution of elevations in skin (Tsk) versus whole body temperatures on exercise capacity has not been characterized. To ascertain their relationships with exercise capacity, blood temperature (TB), oxygen uptake (V̇O2), brain perfusion (MCA Vmean), locomotor limb hemodynamics, and hematological parameters were assessed during incremental cycling exercise with elevated skin (mild hyperthermia; HYPmild), combined core and skin temperatures (moderate hyperthermia; HYPmod), and under control conditions. Both hyperthermic conditions increased Tsk versus control (6.2 ± 0.2°C; P < 0.001), however, only HYPmod increased resting TB, leg blood flow and cardiac output (Q̇), but not MCA Vmean. Throughout exercise, Tsk remained elevated in both hyperthermic conditions, whereas only TB was greater in HYPmod. At exhaustion, oxygen uptake and exercise capacity were reduced in HYPmod in association with lower leg blood flow, MCA Vmean and mean arterial pressure (MAP), but similar maximal heart rate and TB. The attenuated brain and leg perfusion with hyperthermia was associated with a plateau in MCA and two‐legged vascular conductance (VC). Mechanistically, the falling MCA VC was coupled to reductions in PaCO2, whereas the plateau in leg vascular conductance was related to markedly elevated plasma [NA] and a plateau in plasma ATP. These findings reveal that whole‐body hyperthermia, but not skin hyperthermia, compromises exercise capacity in heat‐stressed humans through the early attenuation of brain and active muscle blood flow.
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Affiliation(s)
- Steven J Trangmar
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
| | - Scott T Chiesa
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
| | - Kameljit K Kalsi
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
| | - Niels H Secher
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.,The Copenhagen Muscle Research Centre, Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
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30
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Nuccio RP, Barnes KA, Carter JM, Baker LB. Fluid Balance in Team Sport Athletes and the Effect of Hypohydration on Cognitive, Technical, and Physical Performance. Sports Med 2017; 47:1951-1982. [PMID: 28508338 PMCID: PMC5603646 DOI: 10.1007/s40279-017-0738-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sweat losses in team sports can be significant due to repeated bursts of high-intensity activity, as well as the large body size of athletes, equipment and uniform requirements, and environmental heat stress often present during training and competition. In this paper we aimed to: (1) describe sweat losses and fluid balance changes reported in team sport athletes, (2) review the literature assessing the impact of hypohydration on cognitive, technical, and physical performance in sports-specific studies, (3) briefly review the potential mechanisms by which hypohydration may impact team sport performance, and (4) discuss considerations for future directions. Significant hypohydration (mean body mass loss (BML) >2%) has been reported most consistently in soccer. Although American Football, rugby, basketball, tennis, and ice hockey have reported high sweating rates, fluid balance disturbances have generally been mild (mean BML <2%), suggesting that drinking opportunities were sufficient for most athletes to offset significant fluid losses. The effect of hydration status on team sport performance has been studied mostly in soccer, basketball, cricket, and baseball, with mixed results. Hypohydration typically impaired performance at higher levels of BML (3-4%) and when the method of dehydration involved heat stress. Increased subjective ratings of fatigue and perceived exertion consistently accompanied hypohydration and could explain, in part, the performance impairments reported in some studies. More research is needed to develop valid, reliable, and sensitive sport-specific protocols and should be used in future studies to determine the effects of hypohydration and modifying factors (e.g., age, sex, athlete caliber) on team sport performance.
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Affiliation(s)
- Ryan P Nuccio
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA.
| | - Kelly A Barnes
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - James M Carter
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - Lindsay B Baker
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
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31
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Saini R, Srivastava K, Agrawal S, Das RC. Cognitive deficits due to thermal stress: An exploratory study on soldiers in deserts. Med J Armed Forces India 2017; 73:370-374. [PMID: 29386712 DOI: 10.1016/j.mjafi.2017.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 07/28/2017] [Indexed: 11/26/2022] Open
Abstract
Background It is well known that environmental factors play an important role in human performance. High temperature and humidity particularly impair mental performance by altering brain neurochemistry and electrolyte disturbance which in turn affect one's overall efficiency. While the physiological responses to environmental heat have been well established, it is less clear about its impact on cognition. Study aims to investigate the impact of thermal strain on cognition. Methods One hundred (100) healthy soldiers aged between 20 and 30 years who had spent minimum of one year in desert conditions prior to their induction in the study formed sample of the study. The subjects were evaluated on memory and on cognitive functions twice i.e. in the month of February and June. The data so generated was analyzed by appropriate statistical methods. Results The mean age of the subjects were 25.8 yrs. There was a significant decline in cognitive performance in hot climate as compared to normal weather on Post graduate Institute (PGI) memory scale (P < 0.05). The effect was more marked for tests requiring sustained attention, concentration, psychomotor performance, verbal memory and tests of executive function. Conclusion The present study is the first study to be conducted in actual desert conditions. Findings revealed a detrimental impact of thermal stress on the cognitive performance of soldiers in deserts.
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Affiliation(s)
- Rajiv Saini
- Associate Professor, Department of Psychiatry, Armed Forces Medical College, Pune 411040, India
| | - Kalpana Srivastava
- Scientist 'G', Dept of Psychiatry, Armed Forces Medical College, Pune 411040, India
| | - Sunil Agrawal
- DMS (Health) & Senior Adviser (Community Medicine), Air HQ, Office of DGMS (Air), New Delhi, India
| | - R C Das
- Principal Medical Officer, Eastern Air Command, C/O 99 APO, India
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32
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Williamson E. Nutritional implications for ultra-endurance walking and running events. EXTREME PHYSIOLOGY & MEDICINE 2016; 5:13. [PMID: 27895900 PMCID: PMC5117571 DOI: 10.1186/s13728-016-0054-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 11/01/2016] [Indexed: 01/15/2023]
Abstract
This paper examines the various nutritional challenges which athletes encounter in preparing for and participating in ultra-endurance walking and running events. Special attention is paid to energy level, performance, and recovery within the context of athletes' intake of carbohydrate, protein, fat, and various vitamins and minerals. It outlines, by way of a review of literature, those factors which promote optimal performance for the ultra-endurance athlete and provides recommendations from multiple researchers concerned with the nutrition and performance of ultra-endurance athletes. Despite the availability of some research about the subject, there is a paucity of longitudinal material which examines athletes by nature and type of ultra-endurance event, gender, age, race, and unique physiological characteristics. Optimal nutrition results in a decreased risk of energy depletion, better performance, and quicker full-recovery.
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Affiliation(s)
- Eric Williamson
- Department of Exercise Science, University of Toronto, 55 Harbord Street, Toronto, ON M5S 2W6 Canada
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33
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Volianitis S, Secher NH. Cardiovascular control during whole body exercise. J Appl Physiol (1985) 2016; 121:376-90. [PMID: 27311439 PMCID: PMC5007320 DOI: 10.1152/japplphysiol.00674.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 06/10/2016] [Indexed: 12/25/2022] Open
Abstract
It has been considered whether during whole body exercise the increase in cardiac output is large enough to support skeletal muscle blood flow. This review addresses four lines of evidence for a flow limitation to skeletal muscles during whole body exercise. First, even though during exercise the blood flow achieved by the arms is lower than that achieved by the legs (∼160 vs. ∼385 ml·min(-1)·100 g(-1)), the muscle mass that can be perfused with such flow is limited by the capacity to increase cardiac output (42 l/min, highest recorded value). Secondly, activation of the exercise pressor reflex during fatiguing work with one muscle group limits flow to other muscle groups. Another line of evidence comes from evaluation of regional blood flow during exercise where there is a discrepancy between flow to a muscle group when it is working exclusively and when it works together with other muscles. Finally, regulation of peripheral resistance by sympathetic vasoconstriction in active muscles by the arterial baroreflex is critical for blood pressure regulation during exercise. Together, these findings indicate that during whole body exercise muscle blood flow is subordinate to the control of blood pressure.
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Affiliation(s)
- Stefanos Volianitis
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; and
| | - Niels H Secher
- The Copenhagen Muscle Research Center, Department of Anesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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34
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Akerman AP, Tipton M, Minson CT, Cotter JD. Heat stress and dehydration in adapting for performance: Good, bad, both, or neither? Temperature (Austin) 2016; 3:412-436. [PMID: 28349082 PMCID: PMC5356617 DOI: 10.1080/23328940.2016.1216255] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 01/14/2023] Open
Abstract
Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se. While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans.
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Affiliation(s)
- Ashley Paul Akerman
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago , New Zealand
| | - Michael Tipton
- Extreme Environments Laboratory, Department of Sport & Exercise Science, University of Portsmouth , UK
| | | | - James David Cotter
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago , New Zealand
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35
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O'Reilly J, Cheng HL, Poon ETC. New insights in professional horse racing; "in-race" heart rate data, elevated fracture risk, hydration, nutritional and lifestyle analysis of elite professional jockeys. J Sports Sci 2016; 35:441-448. [PMID: 27070776 DOI: 10.1080/02640414.2016.1171890] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Weight-making practices have been shown to impair musculoskeletal and physiological function of jockeys. This study investigated the "in-race" heart rate (HR) responses and hydration status during competitive racing, as well as selected physiological and lifestyle parameters of professional jockeys based in Hong Kong. "In-race" HR responses and early morning hydration status of 20 male jockeys were examined in hot and moderate climactic occasions. Additionally, bone mineral density (BMD), dietary intake and lifestyle choices were assessed. Osteopenia was observed in the calcanei of jockeys (left: 0.51 ± 0.06; right: 0.46 ± 0.12 g · cm-2). Energy and protein intake were significantly lower on a race day compared to a non-race day (P < 0.05). "In-race" HRmax values were similar to those from VO2max laboratory tests (186 ± 14 vs. 185 ± 8 bpm). Hypohydration was observed on both racing days. (USG: 1.0247 ± 0.006 and 1.0256 ± 0.0258 mg · L-1 for hot and moderate conditions, respectively). Sauna usage (25.5%) and food restriction (20.4%) were the most common weight-making practices. Current lifestyle choices of jockeys result in suboptimal bone health, hydration status and nutritional intake, which can significantly enhance the fracture risk. Further research should develop exercise and nutrition guidelines for optimising their skeletal health.
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Affiliation(s)
- John O'Reilly
- a Department of Sports Science and Physical Education , The Chinese University of Hong Kong , Shatin , Hong Kong
| | - Hoi Lun Cheng
- b Discipline of Exercise and Sport Science, Faculty of Health Sciences , The University of Sydney , Sydney , Australia
| | - Eric Tsz-Chun Poon
- a Department of Sports Science and Physical Education , The Chinese University of Hong Kong , Shatin , Hong Kong
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36
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Abstract
Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up-to-date recommendations to optimize performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimize performance is to heat acclimatize. Heat acclimatization should comprise repeated exercise–heat exposures over 1–2 weeks. In addition, athletes should initiate competition and training in an euhydrated state and minimize dehydration during exercise. Following the development of commercial cooling systems (e.g., cooling vests), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organizers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimizing the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events for hydration and body cooling opportunities when competitions are held in the heat.
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37
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Buono MJ, Krippes T, Kolkhorst FW, Williams AT, Cabrales P. Increases in core temperature counterbalance effects of haemoconcentration on blood viscosity during prolonged exercise in the heat. Exp Physiol 2016; 101:332-42. [PMID: 26682653 PMCID: PMC4738148 DOI: 10.1113/ep085504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 12/15/2015] [Indexed: 01/11/2023]
Abstract
NEW FINDINGS What is the central question of this study? The purpose of the present study was to determine the effects of exercise-induced haemoconcentration and hyperthermia on blood viscosity. What is the main finding and its importance? Exercise-induced haemoconcentration, increased plasma viscosity and increased blood aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell (RBC) deformability (e.g. RBC membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. Previous studies have reported that blood viscosity is significantly increased following exercise. However, these studies measured both pre- and postexercise blood viscosity at 37 °C even though core and blood temperatures would be expected to have increased during the exercise. Consequently, the effect of exercise-induced hyperthermia on mitigating change in blood viscosity may have been missed. The purpose of this study was to isolate the effects of exercise-induced haemoconcentration and hyperthermia and to determine their combined effects on blood viscosity. Nine subjects performed 2 h of moderate-intensity exercise in the heat (37 °C, 40% relative humidity), which resulted in significant increases from pre-exercise values for rectal temperature (from 37.11 ± 0.35 to 38.76 ± 0.13 °C), haemoconcentration (haematocrit increased from 43.6 ± 3.6 to 45.6 ± 3.5%) and dehydration (change in body weight = -3.6 ± 0.7%). Exercise-induced haemoconcentration significantly (P < 0.05) increased blood viscosity by 9% (from 3.97 to 4.33 cP at 300 s(-1)), whereas exercise-induced hyperthermia significantly decreased blood viscosity by 7% (from 3.97 to 3.69 cP at 300 s(-1)). When both factors were considered together, there was no overall change in blood viscosity (from 3.97 to 4.03 cP at 300 s(-1)). The effects of exercise-induced haemoconcentration, increased plasma viscosity and increased red blood cell aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell deformability (e.g. red blood cell membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat.
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Affiliation(s)
- Michael J. Buono
- Department of Biology, San Diego State University, San Diego, CA 92182
- School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA 92182
| | - Taylor Krippes
- School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA 92182
| | - Fred W. Kolkhorst
- School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA 92182
| | - Alexander T. Williams
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093
| | - Pedro Cabrales
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093
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38
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Stookey JJD. Negative, Null and Beneficial Effects of Drinking Water on Energy Intake, Energy Expenditure, Fat Oxidation and Weight Change in Randomized Trials: A Qualitative Review. Nutrients 2016; 8:nu8010019. [PMID: 26729162 PMCID: PMC4728633 DOI: 10.3390/nu8010019] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 12/07/2015] [Accepted: 12/10/2015] [Indexed: 01/08/2023] Open
Abstract
Drinking water has heterogeneous effects on energy intake (EI), energy expenditure (EE), fat oxidation (FO) and weight change in randomized controlled trials (RCTs) involving adults and/or children. The aim of this qualitative review of RCTs was to identify conditions associated with negative, null and beneficial effects of drinking water on EI, EE, FO and weight, to generate hypotheses about ways to optimize drinking water interventions for weight management. RCT conditions that are associated with negative or null effects of drinking water on EI, EE and/or FO in the short term are associated with negative or null effects on weight over the longer term. RCT conditions that are associated with lower EI, increased EE and/or increased FO in the short term are associated with less weight gain or greater weight loss over time. Drinking water instead of caloric beverages decreases EI when food intake is ad libitum. Drinking water increases EE in metabolically-inflexible, obese individuals. Drinking water increases FO when blood carbohydrate and/or insulin concentrations are not elevated and when it is consumed instead of caloric beverages or in volumes that alter hydration status. Further research is needed to confirm the observed associations and to determine if/what specific conditions optimize drinking water interventions for weight management.
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Affiliation(s)
- Jodi J D Stookey
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA.
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39
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Ito K, Saito Y, Yamaguchi M, Ashida K, Yamaji T, Itoh H, Takahashi T, Oda M. Addition of Whey Peptides to a Carbohydrate-electrolyte Drink Enhances its Effect on the Early Treatment of Dehydration in Rats. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2016. [DOI: 10.3136/fstr.22.623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Kentaro Ito
- Food Science Research Labs, R&D Division, Meiji Co., Ltd
| | - Yuri Saito
- Food Science Research Labs, R&D Division, Meiji Co., Ltd
| | | | - Kinya Ashida
- Food Science Research Labs, R&D Division, Meiji Co., Ltd
| | - Taketo Yamaji
- Food Science Research Labs, R&D Division, Meiji Co., Ltd
| | - Hiroyuki Itoh
- Food Science Research Labs, R&D Division, Meiji Co., Ltd
| | - Toru Takahashi
- Graduate School of Human Environment Science, Fukuoka Women's University
| | - Munehiro Oda
- College of Bioresource Sciences, Nihon University
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40
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González-Alonso J, Calbet JAL, Boushel R, Helge JW, Søndergaard H, Munch-Andersen T, van Hall G, Mortensen SP, Secher NH. Blood temperature and perfusion to exercising and non-exercising human limbs. Exp Physiol 2015; 100:1118-31. [PMID: 26268717 PMCID: PMC5049637 DOI: 10.1113/ep085383] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/07/2015] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature- and metabolism-sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature-sensitive mechanisms may contribute to blood-flow regulation, but the influence of temperature on perfusion to exercising and non-exercising human limbs is not established. Blood temperature (TB ), blood flow and oxygen uptake (V̇O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher TB and limb V̇O2. Leg and arm vascular conductance during exercise compared with rest was related closely to TB (r(2) = 0.91; P < 0.05), plasma ATP (r(2) = 0.94; P < 0.05) and limb V̇O2 (r(2) = 0.99; P < 0.05). During incremental leg exercise, LBF increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg exercise were mirrored by similar pulmonary artery TB and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, TB and aerobic metabolism in exercising and non-exercising extremities and a tight association between limb vasodilatation and increases in plasma ATP. These findings suggest that temperature and V̇O2 contribute to the regulation of limb perfusion through control of intravascular ATP.
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Affiliation(s)
- José González-Alonso
- Centre for Sports Medicine and Human Performance, Brunel University London, Uxbridge, UK.,The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - José A L Calbet
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Physical Education, and Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Robert Boushel
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Jørn W Helge
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Centre for Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Søndergaard
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thor Munch-Andersen
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Gerrit van Hall
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Niels H Secher
- The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Denmark
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41
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Keiser S, Flück D, Hüppin F, Stravs A, Hilty MP, Lundby C. Heat training increases exercise capacity in hot but not in temperate conditions: a mechanistic counter-balanced cross-over study. Am J Physiol Heart Circ Physiol 2015; 309:H750-61. [DOI: 10.1152/ajpheart.00138.2015] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/29/2015] [Indexed: 11/22/2022]
Abstract
The aim was to determine the mechanisms facilitating exercise performance in hot conditions following heat training. In a counter-balanced order, seven males (V̇o2max 61.2 ± 4.4 ml·min−1·kg−1) were assigned to either 10 days of 90-min exercise training in 18 or 38°C ambient temperature (30% relative humidity) applying a cross-over design. Participants were tested for V̇o2max and 30-min time trial performance in 18 (T18) and 38°C (T38) before and after training. Blood volume parameters, sweat output, cardiac output (Q̇), cerebral perfusion (i.e., middle cerebral artery velocity [MCAvmean]), and other variables were determined. Before one set of exercise tests in T38, blood volume was acutely expanded by 538 ± 16 ml with an albumin solution (T38A) to determine the role of acclimatization induced hypervolemia on exercise performance. We furthermore hypothesized that heat training would restore MCAvmean and thereby limit centrally mediated fatigue. V̇o2max and time trial performance were equally reduced in T38 and T38A (7.2 ± 1.6 and 9.3 ± 2.5% for V̇o2max; 12.8 ± 2.8 and 12.9 ± 2.8% for time trial). Following heat training both were increased in T38 (9.6 ± 2.1 and 10.4 ± 3.1%, respectively), whereas both V̇o2max and time trial performance remained unchanged in T18. As expected, heat training augmented plasma volume (6 ± 2%) and mean sweat output (26 ± 6%), whereas sweat [Na+] became reduced by 19 ± 7%. In T38 Q̇max remained unchanged before (21.3 ± 0.6 l/min) to after (21.7 ± 0.5 l/min) training, whereas MCAvmean was increased by 13 ± 10%. However, none of the observed adaptations correlated with the concomitant observed changes in exercise performance.
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Affiliation(s)
- Stefanie Keiser
- Zürich Center for Integrative Human Physiology, Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Daniela Flück
- Zürich Center for Integrative Human Physiology, Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Fabienne Hüppin
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zürich, Zürich, Switzerland
| | - Alexander Stravs
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zürich, Zürich, Switzerland
| | - Matthias P. Hilty
- Intensive Care Unit, University Hospital of Zürich, Zürich, Switzerland
| | - Carsten Lundby
- Zürich Center for Integrative Human Physiology, Institute of Physiology, University of Zürich, Zürich, Switzerland
- Food and Nutrition and Sport Science, Gothenburg University, Gothenburg, Sweden
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42
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Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update. Wilderness Environ Med 2015; 25:S55-65. [PMID: 25498263 DOI: 10.1016/j.wem.2014.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.
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Affiliation(s)
- Grant S Lipman
- Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Dr Lipman).
| | - Kurt P Eifling
- Division of Emergency Medicine, Barnes-Jewish Hospital/Washington University School of Medicine, Saint Louis, MO (Dr Eifling)
| | - Mark A Ellis
- Department of Emergency Medicine, Spartanburg Regional Healthcare System, Spartanburg, SC (Dr Eifling)
| | - Flavio G Gaudio
- Division of Emergency Medicine, New York-Presbyterian Hospital/Weill Cornell Medical College, New York, NY (Dr Gaudio)
| | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH (Dr Otten)
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT (Dr Grissom)
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43
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Belhadj Slimen I, Najar T, Ghram A, Abdrrabba M. Heat stress effects on livestock: molecular, cellular and metabolic aspects, a review. J Anim Physiol Anim Nutr (Berl) 2015; 100:401-12. [PMID: 26250521 DOI: 10.1111/jpn.12379] [Citation(s) in RCA: 334] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/12/2015] [Indexed: 11/27/2022]
Abstract
Elevated ambient temperatures affect animal production and welfare. Animal's reduced production performances during heat stress were traditionally thought to result from the decreased feed intake. However, it has recently been shown that heat stress disturbs the steady state concentrations of free radicals, resulting in both cellular and mitochondrial oxidative damage. Indeed, heat stress reorganizes the use of the body resources including fat, protein and energy. Heat stress reduces the metabolic rates and alters post-absorptive metabolism, regardless of the decreased feed intake. Consequently, growth, production, reproduction and health are not priorities any more in the metabolism of heat-stressed animals. The drastic effects of heat stress depend on its duration and severity. This review clearly describes about biochemical, cellular and metabolic changes that occur during thermal stress in farm animals.
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Affiliation(s)
- I Belhadj Slimen
- Department of Animal, Food and Halieutic Resources, National Agronomic Institute of Tunisia, Mahragene city, Tunisia.,Laboratory of Materials, Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, La Marsa, Tunisia
| | - T Najar
- Department of Animal, Food and Halieutic Resources, National Agronomic Institute of Tunisia, Mahragene city, Tunisia.,Laboratory of Materials, Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, La Marsa, Tunisia
| | - A Ghram
- Laboratory of Microbiology, Pasteur Institute of Tunisia, Mahragene city, Tunisia
| | - M Abdrrabba
- Laboratory of Materials, Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, La Marsa, Tunisia
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44
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Priego Quesada JI, Lucas-Cuevas AG, Gil-Calvo M, Giménez JV, Aparicio I, Cibrián Ortiz de Anda RM, Salvador Palmer R, Llana-Belloch S, Pérez-Soriano P. Effects of graduated compression stockings on skin temperature after running. J Therm Biol 2015; 52:130-6. [PMID: 26267507 DOI: 10.1016/j.jtherbio.2015.06.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 11/19/2022]
Abstract
High skin temperatures reduce the thermal gradient between the core and the skin and they can lead to a reduction in performance and increased risk of injury. Graduated compression stockings have become popular among runners in the last years and their use may influence the athlete's thermoregulation. The aim of this study was to investigate the effects of graduated compression stockings on skin temperature during running in a moderate indoor environment. Forty-four runners performed two running tests lasting 30min (10min of warm-up and 20min at 75% of their maximal aerobic speed) with and without graduated compressive stockings. Skin temperature was measured in 12 regions of interest on the lower limb by infrared thermography before and after running. Heart rate and perception of fatigue were assessed during the last minute of the running test. Compression stockings resulted in greater increase of temperature (p=0.002 and ES=2.2, 95% CI [0.11-0.45°C]) not only in the body regions in contact (tibialis anterior, ankle anterior and gastrocnemius) but also in the body regions that were not in contact with the garment (vastus lateralis, abductor and semitendinosus). No differences were observed between conditions in heart rate and perception of fatigue (p>0.05 and ES<0.8). In conclusion, running with graduated compression stockings produces a greater increase of skin temperature without modifying the athlete's heart rate and perception of fatigue.
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Affiliation(s)
- J I Priego Quesada
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain; Biophysics and Medical Physics Group, Department of Physiology, University of Valencia, Valencia, Spain.
| | - A G Lucas-Cuevas
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
| | - M Gil-Calvo
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
| | - J V Giménez
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
| | - I Aparicio
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
| | - R M Cibrián Ortiz de Anda
- Biophysics and Medical Physics Group, Department of Physiology, University of Valencia, Valencia, Spain
| | - R Salvador Palmer
- Biophysics and Medical Physics Group, Department of Physiology, University of Valencia, Valencia, Spain
| | - S Llana-Belloch
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
| | - P Pérez-Soriano
- Research Group in Sport Biomechanics (GIBD), Department of Physical Education and Sports, University of Valencia, Valencia, Spain
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45
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Racinais S, Alonso JM, Coutts AJ, Flouris AD, Girard O, González-Alonso J, Hausswirth C, Jay O, Lee JKW, Mitchell N, Nassis GP, Nybo L, Pluim BM, Roelands B, Sawka MN, Wingo J, Périard JD. Consensus recommendations on training and competing in the heat. Br J Sports Med 2015; 49:1164-73. [PMID: 26069301 PMCID: PMC4602249 DOI: 10.1136/bjsports-2015-094915] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2015] [Indexed: 11/05/2022]
Abstract
Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up-to-date recommendations to optimise performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimise performance is to heat acclimatise. Heat acclimatisation should comprise repeated exercise-heat exposures over 1–2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimise dehydration during exercise. Following the development of commercial cooling systems (eg, cooling-vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organisers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimising the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events, for hydration and body cooling opportunities, when competitions are held in the heat.
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Affiliation(s)
- S Racinais
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - J M Alonso
- Sports Medicine Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar Medical and Anti-doping Commission, International Association of Athletics Federations (IAAF), Montecarlo, Monaco
| | - A J Coutts
- Sport and Exercise Discipline Group, University of Technology Sydney (UTS), Australia
| | - A D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - O Girard
- Department of Physiology, Faculty of Biology and Medicine, ISSUL, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - J González-Alonso
- Department of Life Sciences, Centre for Sports Medicine and Human Performance, College of Health and Life Sciences, Brunel University London, Uxbridge, UK
| | - C Hausswirth
- Research Department, Laboratory of Sport, Expertise and Performance, French National Institute of Sport (INSEP), Paris, France
| | - O Jay
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, Australia
| | - J K W Lee
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - N Mitchell
- British Cycling and 'Sky Pro Cycling', National Cycling Centre, Manchester, UK
| | - G P Nassis
- National Sports Medicine Programme, Excellence in Football Project, Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - L Nybo
- Department of Nutrition, Exercise and Sport, Section of Human Physiology, University of Copenhagen, Copenhagen, Denmark
| | - B M Pluim
- Medical Department, Royal Netherlands Lawn Tennis Association (KNLTB), Amersfoort, The Netherlands
| | - B Roelands
- Department of Human Physiology, Vrije Universiteit Brussel, Brussels, Belgium
| | - M N Sawka
- School of Applied Physiology, College of Science, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - J Wingo
- Department of Kinesiology, University of Alabama, Tuscaloosa, USA
| | - J D Périard
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
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46
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Racinais S, Alonso JM, Coutts AJ, Flouris AD, Girard O, González-Alonso J, Hausswirth C, Jay O, Lee JKW, Mitchell N, Nassis GP, Nybo L, Pluim BM, Roelands B, Sawka MN, Wingo JE, Périard JD. Consensus recommendations on training and competing in the heat. Scand J Med Sci Sports 2015; 25 Suppl 1:6-19. [DOI: 10.1111/sms.12467] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2015] [Indexed: 11/26/2022]
Affiliation(s)
- S. Racinais
- Athlete Health and Performance Research Centre; Aspetar; Qatar Orthopaedic and Sports Medicine Hospital; Doha Qatar
| | - J. M. Alonso
- Sports Medicine Department; Aspetar Orthopaedic and Sports Medicine Hospital; Doha Qatar
- Medical and Anti-doping Commission; International Association of Athletics Federations (IAAF); Montecarlo Monaco
| | - A. J. Coutts
- Sport and Exercise Discipline Group; University of Technology Sydney (UTS); Lindfield New South Wales Australia
| | - A. D. Flouris
- FAME Laboratory; Department of Physical Education and Sport Science; University of Thessaly; Trikala Greece
| | - O. Girard
- ISSUL; Institute of Sport Sciences; Department of Physiology; Faculty of Biology and Medicine; University of Lausanne; Lausanne Switzerland
| | - J. González-Alonso
- Centre for Sports Medicine and Human Performance; Department of Life Sciences; College of Health and Life Sciences; Brunel University London; Uxbridge UK
| | - C. Hausswirth
- French National Institute of Sport (INSEP); Research Department; Laboratory of Sport, Expertise and Performance; Paris France
| | - O. Jay
- Discipline of Exercise and Sport Science; Faculty of Health Sciences; University of Sydney; Lidcombe New South Wales Australia
| | - J. K. W. Lee
- Defence Medical and Environmental Research Institute; DSO National Laboratories; Singapore
- Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- Lee Kong Chian School of Medicine; Nanyang Technological University; Singapore
| | - N. Mitchell
- British Cycling and “Sky Pro Cycling”; National Cycling Centre; Manchester UK
| | - G. P. Nassis
- National Sports Medicine Programme; Excellence in Football Project; Aspetar; Qatar Orthopaedic and Sports Medicine Hospital; Doha Qatar
| | - L. Nybo
- Department of Nutrition, Exercise and Sport; Section of Human Physiology; University of Copenhagen; Copenhagen Denmark
| | - B. M. Pluim
- Medical Department; Royal Netherlands Lawn Tennis Association (KNLTB); Amersfoort The Netherlands
| | - B. Roelands
- Department of Human Physiology; Vrije Universiteit Brussel; Brussels Belgium
| | - M. N. Sawka
- School of Applied Physiology; College of Science; Georgia Institute of Technology; Atlanta Georgia USA
| | - J. E. Wingo
- Department of Kinesiology; University of Alabama; Tuscaloosa Alabama USA
| | - J. D. Périard
- Athlete Health and Performance Research Centre; Aspetar; Qatar Orthopaedic and Sports Medicine Hospital; Doha Qatar
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47
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Nybo L, González-Alonso J. Critical core temperature: a hypothesis too simplistic to explain hyperthermia-induced fatigue. Scand J Med Sci Sports 2015; 25 Suppl 1:4-5. [DOI: 10.1111/sms.12444] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- L. Nybo
- Department of Exercise and Sport Sciences, Section of Human Physiology; University of Copenhagen; Copenhagen Denmark
| | - J. González-Alonso
- Centre for Sports Medicine and Human Performance; Brunel University London; Uxbridge UK
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48
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Fernández-Elías VE, Hamouti N, Ortega JF, Mora-Rodríguez R. Hyperthermia, but not muscle water deficit, increases glycogen use during intense exercise. Scand J Med Sci Sports 2015; 25 Suppl 1:126-34. [DOI: 10.1111/sms.12368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2014] [Indexed: 11/30/2022]
Affiliation(s)
| | - N. Hamouti
- Exercise Physiology Laboratory; University of Castilla - La Mancha; Toledo Spain
| | - J. F. Ortega
- Exercise Physiology Laboratory; University of Castilla - La Mancha; Toledo Spain
| | - R. Mora-Rodríguez
- Exercise Physiology Laboratory; University of Castilla - La Mancha; Toledo Spain
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49
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James CA, Richardson AJ, Watt PW, Gibson OR, Maxwell NS. Physiological responses to incremental exercise in the heat following internal and external precooling. Scand J Med Sci Sports 2015; 25 Suppl 1:190-9. [DOI: 10.1111/sms.12376] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2014] [Indexed: 11/28/2022]
Affiliation(s)
- C. A. James
- Environmental Extremes Laboratory; Centre for Sport and Exercise Science and Medicine (SESAME); University of Brighton; Eastbourne UK
| | - A. J. Richardson
- Environmental Extremes Laboratory; Centre for Sport and Exercise Science and Medicine (SESAME); University of Brighton; Eastbourne UK
| | - P. W. Watt
- Environmental Extremes Laboratory; Centre for Sport and Exercise Science and Medicine (SESAME); University of Brighton; Eastbourne UK
| | - O. R. Gibson
- Environmental Extremes Laboratory; Centre for Sport and Exercise Science and Medicine (SESAME); University of Brighton; Eastbourne UK
| | - N. S. Maxwell
- Environmental Extremes Laboratory; Centre for Sport and Exercise Science and Medicine (SESAME); University of Brighton; Eastbourne UK
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50
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Non-invasive estimation of hydration status changes through tear fluid osmolarity during exercise and post-exercise rehydration. Eur J Appl Physiol 2015; 115:1165-75. [PMID: 25576262 DOI: 10.1007/s00421-015-3099-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 01/04/2015] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine if tear fluid osmolarity (Tosm) can track changes in hydration status during exercise and post-exercise rehydration. METHODS Nineteen male athletes (18-37 years, 74.6 ± 7.9 kg) completed two randomized, counterbalanced trials; cycling (~95 min) with water intake to replace fluid losses or water restriction to progressively dehydrate to 3 % body mass loss (BML). After exercise, subjects drank water to maintain body mass (water intake trials) or progressively rehydrate to pre-exercise body mass (water restriction trials) over a 90-min recovery period. Plasma osmolality (Posm) and Tosm measurements (mean of right and left eyes) were taken pre-exercise, during rest periods between exercise bouts corresponding to 1, 2, and 3 % BML, and rehydration at 2, 1, and 0 % BML. RESULTS During exercise mean (± SD) Tosm was significantly higher in water restriction vs. water intake trials at 1 % BML (299 ± 9 vs. 293 ± 9 mmol/L), 2 % BML (301 ± 9 vs. 294 ± 9 mmol/L), and 3 % BML (302 ± 9 vs. 292 ± 8 mmol/L). Mean Tosm progressively decreased during post-exercise rehydration and was not different between trials at 1 % BML (291 ± 8 vs. 290 ± 7 mmol/L) and 0 % BML (288 ± 7 vs. 289 ± 8 mmol/L). Mean Tosm tracked changes in hydration status similar to that of mean Posm; however, the individual responses in Tosm to water restriction and water intake was considerably more variable than that of Posm. CONCLUSION Tosm is a valid indicator of changes in hydration status when looking at the group mean; however, large differences among subjects in the Tosm response to hydration changes limit its validity for individual recommendations.
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