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Callovini A, Fornasiero A, Savoldelli A, Decet M, Skafidas S, Pellegrini B, Bortolan L, Schena F. Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise. Eur J Appl Physiol 2024; 124:1185-1200. [PMID: 37962573 PMCID: PMC10955012 DOI: 10.1007/s00421-023-05343-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/16/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To evaluate the independent and combined effects of hypoxia (FiO2 = 13.5%) and cold (- 20 °C) on physiological and perceptual responses to endurance exercise. METHODS 14 trained male subjects ( V . O2max: 64 ± 5 mL/kg/min) randomly performed a discontinuous maximal incremental test to exhaustion on a motorized treadmill under four environmental conditions: Normothermic-Normoxia (N), Normothermic-Hypoxia (H), Cold-Normoxia (C) and Cold-Hypoxia (CH). Performance and physiological and perceptual responses throughout exercise were evaluated. RESULTS Maximal WorkLoad (WL) and WL at lactate threshold (LT) were reduced in C (- 2.3% and - 3.5%) and H (- 18.0% and - 21.7%) compared to N, with no interactive (p = 0.25 and 0.81) but additive effect in CH (- 21.5% and - 24.6%). Similarly, HRmax and Vemax were reduced in C (- 3.2% and - 14.6%) and H (- 5.0% and - 7%), showing additive effects in CH (- 7.7% and - 16.6%). At LT, additive effect of C (- 2.8%) and H (- 3.8%) on HR reduction in CH (- 5.7%) was maintained, whereas an interactive effect (p = 0.007) of the two stressors combined was noted on Ve (C: - 3.1%, H: + 5.5%, CH: - 10.9%). [La] curve shifted on the left in CH, displaying an interaction effect between the 2 stressors on this parameter. Finally, RPE at LT was exclusively reduced by hypoxia (p < 0.001), whereas TSmax is synergistically reduced by cold and hypoxia (interaction p = 0.047). CONCLUSION If compared to single stress exposure, exercise performance and physiological and perceptual variables undergo additive or synergistic effects when cold and hypoxia are combined. These results provide new insight into human physiological responses to extreme environments.
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Affiliation(s)
- A Callovini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy.
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - A Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - A Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | - M Decet
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - S Skafidas
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - B Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - L Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - F Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Bottenheft C, Groen EL, Mol D, Valk PJL, Houben MMJ, Kingma BRM, van Erp JBF. Effects of heat load and hypobaric hypoxia on cognitive performance: a combined stressor approach. ERGONOMICS 2023; 66:2148-2164. [PMID: 36916391 DOI: 10.1080/00140139.2023.2190062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
This study investigates how cognitive performance is affected by the combination of two stressors that are operationally relevant for helicopter pilots: heat load and hypobaric hypoxia. Fifteen participants were exposed to (1) no stressors, (2) heat load, (3) hypobaric hypoxia, and (4) combined heat load and hypobaric hypoxia. Hypobaric hypoxia (13,000 ft) was achieved in a hypobaric chamber. Heat load was induced by increasing ambient temperature to ∼28 °C. Cognitive performance was measured using two multitasks, and a vigilance task. Subjective and physiological data (oxygen saturation, heart rate, core- and skin temperature) were also collected. Mainly heat load caused cognitive performance decline. This can be explained by high subjective heat load and increased skin temperature, which takes away cognitive resources from the tasks. Only the arithmetic subtask was sensitive to hypobaric hypoxia, whereby hypobaric hypoxia caused a further performance decline in addition to the decline caused by heat load.Practitioner summary: Little is known about how multiple environmental stressors interact. This study investigates the combined effects of heat load and hypobaric hypoxia on cognitive performance. An additive effect of heat load and hypobaric hypoxia was found on a arithmetic task, which may be attributed to independent underlying mechanisms.
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Affiliation(s)
- Charelle Bottenheft
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
- Human Media Interaction, Computer Science, University of Twente, Enschede, Netherlands
| | - Eric L Groen
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Douwe Mol
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Pierre J L Valk
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Mark M J Houben
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Boris R M Kingma
- Department of Human Performance, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
| | - Jan B F van Erp
- Human Media Interaction, Computer Science, University of Twente, Enschede, Netherlands
- Department of Human Machine Teaming, Unit Defence, Safety and Security, Netherlands Organisation for Applied Scientific Research (TNO), Soesterberg, Netherlands
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Salmon OF, Segovia MD, Ugale CB, Smith CM. The impact of cold, hypoxia, and physical exertion on pistol accuracy and tactical performance. J Therm Biol 2023; 117:103676. [PMID: 37738801 DOI: 10.1016/j.jtherbio.2023.103676] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 09/24/2023]
Abstract
The purpose of this study was to examine the impact of independent cold and combined cold and hypoxic exposures on operational-specific task performance including pistol marksmanship, pistol magazine reload ability, and subjective and objective thermal indices before and after a whole-body physical exertional task. Twelve participants were exposed to Thermoneutral Normoxic (24 °C; FiO2 21%), Cold Normoxic (10 °C; FiO2 21%), and Cold Hypoxic (10 °C; FiO2 14%) conditions for 30min before performing pistol marksmanship at distances of 6.40 and 13.72m and a pistol magazine reload task before and after 3 sets of sandbag deadlifts at 50% body mass. Thermal perception and hand temperatures were collected before and after the physical exertion task. There were no significant differences in Pistol Accuracy performance at distances of 6.40 and 13.72m due to physical exertion, cold, or hypoxia. Following physical exertion, Pistol Accuracy was similar between Thermoneutral and Cold Normoxic conditions but lead to 17% and a 10% reduction in performance during the Cold Hypoxic condition, compared to Thermoneutral and Cold Normoxic conditions. There was no change in Pistol Accuracy for the Thermoneutral Normoxic condition. The pistol magazine reload task was not impacted by physical exertion, but there was a reduction in performance in Cold Normoxic 21% (4.04s) and Cold Hypoxic 16% (3.08s) conditions. Physical exertion did not impact hand temperature but did increase thermal perception scores for all conditions. These findings indicate that cold exposure reduced both tactical dexterity and pistol marksmanship, however, physical exertion may offset these deficits via an increase in thermal perception. Additionally, hypoxemia was the primary mediator of marksmanship performance in cold hypoxic environments following an acute bout of physical exertion. Thus, in cold mountainous environments, marksmen should be aware of their elevation and utilize brief episodes of physical activity to enhance their thermal state when marksmanship is a priority for operational success.
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Affiliation(s)
- Owen F Salmon
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Matt D Segovia
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Cierra B Ugale
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Cory M Smith
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA.
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Matias AA, Albin IF, Glickman L, Califano PA, Faller JM, Layec G, Ives SJ. Impact of high intensity interval exercise with and without heat stress on cardiovascular and aerobic performance: a pilot study. BMC Sports Sci Med Rehabil 2023; 15:83. [PMID: 37434243 DOI: 10.1186/s13102-023-00682-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 06/21/2023] [Indexed: 07/13/2023]
Abstract
BACKGROUND Heat stress during aerobic exercise training may offer an additional stimulus to improve cardiovascular function and performance in a cool-temperate environment. However, there is a paucity of information on the additive effects of high-intensity interval exercise (HIIE) and acute heat stress. We aimed to determine the effects of HIIE in combination with acute heat stress on cardiovascular function and exercise performance. METHODS Twelve active (peak O2 consumption [VO2peak]: 47 ± 8 ml·O2/min/kg) young adults were counterbalanced to six sessions of HIIE in hot (HIIE-H, 30 ± 1 °C, 50 ± 5% relative humidity [RH]) or temperate conditions (HIIE-T, 20 ± 2 °C, 15 ± 10% RH). Resting heart rate (HR), HR variability (HRV), central (cBP) and peripheral blood pressure (pBP), peripheral mean arterial pressure (pMAP), pulse wave velocity (PWV), VO2peak, and 5-km treadmill time-trial were measured pre- and post-training. RESULTS Resting HR and HRV were not significantly different between groups. However, expressed as percent change from baseline, cSBP (HIIE-T: + 0.9 ± 3.6 and HIIE-H: -6.6 ± 3.0%, p = 0.03) and pSBP (HIIE-T: -2.0 ± 4.6 and HIIE-H: -8.4 ± 4.7%, p = 0.04) were lower in the heat group. Post-training PWV was also significantly lower in the heat group (HIIE-T: + 0.4% and HIIE-H: -6.3%, p = 0.03). Time-trial performance improved with training when data from both groups were pooled, and estimated VO2peak was not significantly different between groups (HIIE-T: 0.7% and HIIE-H: 6.0%, p = 0.10, Cohen's d = 1.4). CONCLUSIONS The addition of acute heat stress to HIIE elicited additive adaptations in only cardiovascular function compared to HIIE alone in active young adults in temperate conditions, thus providing evidence for its effectiveness as a strategy to amplify exercise-induced cardiovascular adaptations.
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Affiliation(s)
- Alexs A Matias
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
| | - Isabelle F Albin
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Leah Glickman
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Peter A Califano
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Justin M Faller
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Gwenael Layec
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
- Institute for Applied Life Sciences, University of Massachusetts, Amherst, MA, USA
| | - Stephen J Ives
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA.
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Wait SO, Charkoudian N, Skinner JW, Smith CJ. Combining hypoxia with thermal stimuli in humans: physiological responses and potential sex differences. Am J Physiol Regul Integr Comp Physiol 2023; 324:R677-R690. [PMID: 36971421 PMCID: PMC10202487 DOI: 10.1152/ajpregu.00244.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
Increasing prevalence of native lowlanders sojourning to high altitudes (>2,500 m) for recreational, occupational, military, and competitive reasons has generated increased interest in physiological responses to multistressor environments. Exposure to hypoxia poses recognized physiological challenges that are amplified during exercise and further complicated by environments that might include combinations of heat, cold, and high altitude. There is a sparsity of data examining integrated responses in varied combinations of environmental conditions, with even less known about potential sex differences. How this translates into performance, occupational, and health outcomes requires further investigation. Acute hypoxic exposure decreases arterial oxygen saturation, resulting in a reflex hypoxic ventilatory response and sympathoexcitation causing an increase in heart rate, myocardial contractility, and arterial blood pressure, to compensate for the decreased arterial oxygen saturation. Acute altitude exposure impairs exercise performance, for example, reduced time to exhaustion and slower time trials, largely owing to impairments in pulmonary gas exchange and peripheral delivery resulting in reduced V̇o2max. This exacerbates with increasing altitude, as does the risk of developing acute mountain sickness and more serious altitude-related illnesses, but modulation of those risks with additional stressors is unclear. This review aims to summarize and evaluate current literature regarding cardiovascular, autonomic, and thermoregulatory responses to acute hypoxia, and how these may be affected by simultaneous thermal environmental challenges. There is minimal available information regarding sex as a biological variable in integrative responses to hypoxia or multistressor environments; we highlight these areas as current knowledge gaps and the need for future research.
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Affiliation(s)
- Seaver O Wait
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Nisha Charkoudian
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Jared W Skinner
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Caroline J Smith
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
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Lloyd A, Fiala D, Heyde C, Havenith G. A mathematical model for predicting cardiovascular responses at rest and during exercise in demanding environmental conditions. J Appl Physiol (1985) 2022; 133:247-261. [PMID: 35652831 PMCID: PMC9342140 DOI: 10.1152/japplphysiol.00619.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present research describes the development and validation of a cardiovascular model (CVR Model) for use in conjunction with advanced thermophysiological models, where usually only a total cardiac output is estimated. The CVR Model detailed herein estimates cardio-dynamic parameters (changes in cardiac output, stroke volume, and heart rate), regional blood flow, and muscle oxygen extraction, in response to rest and physical workloads, across a range of ages and aerobic fitness levels, as well as during exposure to heat, dehydration, and altitude. The model development strategy was to first establish basic resting and exercise predictions for cardio-dynamic parameters in an "ideal" environment (cool, sea level, and hydrated person). This basic model was then advanced for increasing levels of altitude, heat strain, and dehydration, using meta-analysis and reaggregation of published data. Using the estimated altitude- and heat-induced changes in maximum oxygen extraction and maximum cardiac output, the decline in maximum oxygen consumption at high altitude and in the heat was also modeled. A validation of predicted cardiovascular strain using heart rate was conducted using a dataset of 101 heterogeneous individuals (1,371 data points) during rest and exercise in the heat and at altitude, demonstrating that the CVR Model performs well (R2 = 0.82-0.84) in predicting cardiovascular strain, particularly at a group mean level (R2 = 0.97). The development of the CVR Model is aimed at providing the Fiala thermal Physiology & Comfort (FPC) Model and other complex thermophysiological models with improved estimations of cardiac strain and exercise tolerance, across a range of individuals during acute exposure to environmental stressors.NEW & NOTEWORTHY The present research promotes the adaption of thermophysiological modeling to the estimation of cardiovascular strain in individuals exercising under acute environmental stress. Integration with advanced models of human thermoregulation opens doors for detailed numerical analysis of athletes' performance and physiology during exercise, occupational safety, and individual work tolerability. The research provides a simple-to-validate metric of cardiovascular function (heart rate), as well as a method to evaluate key principles influencing exercise- and thermoregulation in humans.
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Affiliation(s)
- Alex Lloyd
- 1Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Dusan Fiala
- 2ERGONSIM—Human Thermal Modelling, Messstetten, Germany
| | | | - George Havenith
- 1Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
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O'Keeffe K, Dean J, Hodder S, Lloyd A. Self-Selected Motivational Music Enhances Physical Performance in Normoxia and Hypoxia in Young Healthy Males. Front Psychol 2021; 12:787496. [PMID: 34956012 PMCID: PMC8702523 DOI: 10.3389/fpsyg.2021.787496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
Humans exposed to hypoxia are susceptible to physiological and psychological impairment. Music has ergogenic effects through enhancing psychological factors such as mood, emotion, and cognition. This study aimed to investigate music as a tool for mitigating the performance decrements observed in hypoxia. Thirteen males (mean ± SD; 24 ± 4 years) completed one familiarization session and four experimental trials; (1) normoxia (sea level, 0.209 FiO2) and no music; (2) normoxia (0.209 FiO2) with music; (3) normobaric hypoxia (∼3800 m, 0.13 FiO2) and no music; and (4) normobaric hypoxia (0.13 FiO2) with music. Experimental trials were completed at 21°C with 50% relative humidity. Music was self-selected prior to the familiarization session. Each experimental trial included a 15-min time trial on an arm bike, followed by a 60-s isometric maximal voluntary contraction (MVC) of the biceps brachii. Supramaximal nerve stimulation quantified central and peripheral fatigue with voluntary activation (VA%) calculated using the doublet interpolation method. Average power output (W) was reduced with a main effect of hypoxia (p = 0.02) and significantly increased with a main effect of music (p = 0.001). When combined the interaction was additive (p = 0.87). Average MVC force (N) was reduced in hypoxia (p = 0.03) but VA% of the biceps brachii was increased with music (p = 0.02). Music reduced subjective scores of mental effort, breathing discomfort, and arm discomfort in hypoxia (p < 0.001). Music increased maximal physical exertion through enhancing neural drive and diminishing detrimental mental processes, enhancing performance in normoxia (6.3%) and hypoxia (6.4%).
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Affiliation(s)
- Kate O'Keeffe
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Jacob Dean
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Alex Lloyd
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
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Gatterer H, Dünnwald T, Turner R, Csapo R, Schobersberger W, Burtscher M, Faulhaber M, Kennedy MD. Practicing Sport in Cold Environments: Practical Recommendations to Improve Sport Performance and Reduce Negative Health Outcomes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:9700. [PMID: 34574624 PMCID: PMC8471173 DOI: 10.3390/ijerph18189700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 11/17/2022]
Abstract
Although not a barrier to perform sport, cold weather environments (low ambient temperature, high wind speeds, and increased precipitation, i.e., rain/water/snow) may influence sport performance. Despite the obvious requirement for practical recommendations and guidelines to better facilitate training and competition in such cold environments, the current scientific evidence-base is lacking. Nonetheless, this review summarizes the current available knowledge specifically related to the physiological impact of cold exposure, in an attempt to provide practitioners and coaches alike with practical recommendations to minimize any potential negative performance effects, mitigate health issues, and best optimize athlete preparation across various sporting disciplines. Herein, the review is split into sections which explore some of the key physiological effects of cold exposure on performance (i.e., endurance exercise capacity and explosive athletic power), potential health issues (short-term and long-term), and what is currently known with regard to best preparation or mitigation strategies considered to negate the potential negative effects of cold on performance. Specific focus is given to "winter" sports that are usually completed in cold environments and practical recommendations for physical preparation.
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Affiliation(s)
- Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bolzano, Italy;
| | - Tobias Dünnwald
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT, Private University for Health Sciences, Medical Informatics and Technology, 6060 Hall i.T., Tirol, Austria and Tirol-Kliniken GmbH, 6020 Innsbruck, Austria; (T.D.); (W.S.)
| | - Rachel Turner
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bolzano, Italy;
| | - Robert Csapo
- Centre for Sport Science and University Sports, University of Vienna, 1010 Vienna, Austria;
| | - Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT, Private University for Health Sciences, Medical Informatics and Technology, 6060 Hall i.T., Tirol, Austria and Tirol-Kliniken GmbH, 6020 Innsbruck, Austria; (T.D.); (W.S.)
- Austrian Society for Alpine and High-Altitude Medicine, 6414 Mieming, Austria; (M.B.); (M.F.)
| | - Martin Burtscher
- Austrian Society for Alpine and High-Altitude Medicine, 6414 Mieming, Austria; (M.B.); (M.F.)
- Department of Sport Science, University Innsbruck, 6020 Innsbruck, Austria
| | - Martin Faulhaber
- Austrian Society for Alpine and High-Altitude Medicine, 6414 Mieming, Austria; (M.B.); (M.F.)
- Department of Sport Science, University Innsbruck, 6020 Innsbruck, Austria
| | - Michael D. Kennedy
- Athlete Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB T6G 2R3, Canada;
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Neuromuscular Adaptations after an Altitude Training Camp in Elite Judo Athletes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18136777. [PMID: 34202491 PMCID: PMC8296934 DOI: 10.3390/ijerph18136777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 11/17/2022]
Abstract
The aim of this study was to investigate neuromuscular adaptations in elite judo athletes after three weeks of power-oriented strength training at terrestrial altitude (2320 m). Nineteen men were assigned to altitude training (AL) (22.1 ± 2.3 years) and sea level training (SL) (22.6 ± 4.1 years). Neuromuscular assessment consisted of: (1) maximal isometric knee extensor (KE) torque, (2) KE rate of torque development (RTD), (3) quadriceps activity and voluntary activation, (4) soleus H-reflex, (5) quadriceps single (TTW) and double twitch torque (TDB100) and contraction time (CTTW). There were no significant differences between groups at baseline for any of the observed parameters. Significant differences were found between groups in terms of change in RTD (p = 0.04). Cohen’s d showed a positive significant effect (0.43) in the SL group and a negative significant effect (−0.58) in the AL group. The difference between groups in changes in CTTW as a function of altitude was on the edge of significance (p = 0.077). CTTW increased by 8.1 ± 9.0% in the AL group (p = 0.036) and remained statistically unchanged in the SL group. Only the AL group showed a relationship between changes in TTW and TDB100 and changes in RTD at posttest (p = 0.022 and p = 0.016, respectively). Altitude induced differences in muscular adaptations likely due to greater peripheral fatigue.
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10
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Durand F, Raberin A. Exercise-Induced Hypoxemia in Endurance Athletes: Consequences for Altitude Exposure. Front Sports Act Living 2021; 3:663674. [PMID: 33981992 PMCID: PMC8107360 DOI: 10.3389/fspor.2021.663674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/25/2021] [Indexed: 11/26/2022] Open
Abstract
Exercise-induced hypoxemia (EIH) is well-described in endurance-trained athletes during both maximal and submaximal exercise intensities. Despite the drop in oxygen (O2) saturation and provided that training volumes are similar, athletes who experience EIH nevertheless produce the same endurance performance in normoxia as athletes without EIH. This lack of a difference prompted trainers to consider that the phenomenon was not relevant to performance but also suggested that a specific adaptation to exercise is present in EIH athletes. Even though the causes of EIH have been extensively studied, its consequences have not been fully characterized. With the development of endurance outdoor activities and altitude/hypoxia training, athletes often train and/or compete in this stressful environment with a decrease in the partial pressure of inspired O2 (due to the drop in barometric pressure). Thus, one can reasonably hypothesize that EIH athletes can specifically adapt to hypoxemic episodes during exercise at altitude. Although our knowledge of the interactions between EIH and acute exposure to hypoxia has improved over the last 10 years, many questions have yet to be addressed. Firstly, endurance performance during acute exposure to altitude appears to be more impaired in EIH vs. non-EIH athletes but the corresponding physiological mechanisms are not fully understood. Secondly, we lack information on the consequences of EIH during chronic exposure to altitude. Here, we (i) review research on the consequences of EIH under acute hypoxic conditions, (ii) highlight unresolved questions about EIH and chronic hypoxic exposure, and (iii) suggest perspectives for improving endurance training.
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Affiliation(s)
- Fabienne Durand
- Images Espace Dev, Université de Perpignan Via Domitia, Perpignan, France
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11
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Temel M, Johnson AA, Havenith G, Arnold JT, West AM, Lloyd AB. An examination of five theoretical foundations associated with localized thermosensory testing. Eur J Appl Physiol 2021; 121:1943-1954. [PMID: 33765169 PMCID: PMC8192324 DOI: 10.1007/s00421-021-04670-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/16/2021] [Indexed: 11/05/2022]
Abstract
Purpose To assess five theoretical foundations underlying thermosensory testing using local thermal stimuli. Methods Thermal sensation, discomfort and the confidence of thermal sensation scores were measured in 9 female and 8 male volunteers in response to 17 physical contact temperature stimuli, ranging between 18–42 °C. These were applied to their dorsal forearm and lateral torso, across two sessions. Results Thermal sensation to physical temperature relationships followed a positive linear and sigmoidal fit at both forearm (r2 = 0.91/r2 = 0.91, respectively) and lateral torso (r2 = 0.90/ r2 = 0.91, respectively). Thermal discomfort to physical temperature relationships followed second and third-order fits at both forearm (r2 = 0.33/r2 = 0.34, respectively) and lateral torso (r2 = 0.38/r2 = 0.39, respectively) test sites. There were no sex-related or regional site differences in thermal sensation and discomfort across a wide range of physical contact temperatures. The median confidence of an individual’s thermal sensation rating was measured at 86%. Conclusion The relation between thermal sensation and physical contact temperature was well described by both linear and sigmoidal models, i.e., the distance between the thermal sensation anchors is close to equal in terms of physical temperatures changes for the range studied. Participants rated similar thermal discomfort level in both cold and hot thermal stimuli for a given increase or decrease in physical contact temperature or thermal sensation. The confidence of thermal sensation rating did not depend on physical contact temperature.
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Affiliation(s)
- Mevra Temel
- School of Design and Creative Arts, Loughborough University, Loughborough, UK.,Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Andrew A Johnson
- School of Design and Creative Arts, Loughborough University, Loughborough, UK
| | - George Havenith
- School of Design and Creative Arts, Loughborough University, Loughborough, UK.,Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Josh T Arnold
- School of Design and Creative Arts, Loughborough University, Loughborough, UK.,Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Anna M West
- School of Design and Creative Arts, Loughborough University, Loughborough, UK.,Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Alex B Lloyd
- School of Design and Creative Arts, Loughborough University, Loughborough, UK. .,Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK.
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12
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O'Keeffe K, Raccuglia G, Hodder S, Lloyd A. Mental fatigue independent of boredom and sleepiness does not impact self-paced physical or cognitive performance in normoxia or hypoxia. J Sports Sci 2021; 39:1687-1699. [PMID: 33678152 DOI: 10.1080/02640414.2021.1896104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
This study investigated the individual and combined effects of mental fatigue (MF) and hypoxia (HYP) on physical and cognitive performance. Fifteen males (24 ± 3 years) completed one familiarization session and six experimental trials, including: 1) normoxia (0.209 FiO2) and no MF; 2) normoxia (0.209 FiO2) with MF; 3) mild normobaric HYP (0.13 FiO2) and no MF; 4) mild normobaric HYP (0.13 FiO2) with MF; 5) severe normobaric HYP (0.10 FiO2) and no MF; 6) severe normobaric HYP (0.10 FiO2) with MF. Each condition included a 15-min self-paced time trial, followed by a 60-s isometric maximal voluntary contraction of the biceps brachii. MF was induced using a 16-min individualized cognitive test prior to exercise performance. Following each time trial, participants performed the Tower of Hanoi cognitive test. A main effect of HYP was observed on average power output, oxygen consumption and muscle oxygenation (P ≤ 0.004), with no effect of MF (P ≥ 0.599). Voluntary activation of the biceps brachii was also reduced in HYP (68.42 ± 5.64%, P = 0.039). No effect of MF or HYP was observed on cognitive performance (P ≥ 0.138). HYP impacted physical performance, whilst MF had no effect on self-paced physical or cognitive performance.
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Affiliation(s)
- Kate O'Keeffe
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Giuseppe Raccuglia
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
| | - Alex Lloyd
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, UK
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13
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Valenza A, Charlier H, Bianco A, Filingeri D. Independent and interactive effects of thermal stress and mental fatigue on manual dexterity. Am J Physiol Regul Integr Comp Physiol 2020; 319:R703-R711. [PMID: 33074012 DOI: 10.1152/ajpregu.00226.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many occupations and sports require high levels of manual dexterity under thermal stress and mental fatigue. Yet, multistressor studies remain scarce. We quantified the interactive effects of thermal stress and mental fatigue on manual dexterity. Seven males (21.1 ± 1.3 yr) underwent six separate 60-min trials characterized by a combination of three air temperatures (hot, 37°C; neutral, 21°C; cold, 7°C) and two mental fatigue states (MF, mental fatigue induced by a 35-min cognitive battery; no-MF, no mental fatigue). Participants performed complex (O'Connor test) and simple (hand-tool test) manual tasks pre- and posttrial to determine stressor-induced performance changes. We monitored participants' rectal temperature and hand skin temperature (Thand) continuously and assessed the reaction time (hand-click test) and subjective mental fatigue (5-point scale). Thermal stress (P < 0.0001), but not mental fatigue (P = 0.290), modulated Thand (heat, +3.3°C [95% CI: +0.2, +6.5]; cold, -7.5°C [-10.7, -4.4]). Mental fatigue (P = 0.021), but not thermal stress (P = 0.646), slowed the reaction time (∼10%) and increased subjective fatigue. Thermal stress and mental fatigue had an interactive effect on the complex manual task (P = 0.040), with cold-no-MF decreasing the performance by -22% [-39, -5], whereas neutral-MF, cold-MF, and heat-MF by -36% [-53, -19], -34% [-52, -17], and -36% [-53, -19], respectively. Only mental fatigue decreased the performance in the simple manual task (-30% [-43, -16] across all thermal conditions; P = 0.002). Cold stress-induced impairments in complex manipulation increase with mental fatigue; yet combined stressors' effects are no greater than those of mental fatigue alone, which also impairs simple manipulation. Mental fatigue poses a greater challenge to manual dexterity than thermal stress.
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Affiliation(s)
- Alessandro Valenza
- THERMOSENSELAB, Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom.,Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Harry Charlier
- THERMOSENSELAB, Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Antonino Bianco
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Davide Filingeri
- THERMOSENSELAB, Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
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14
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Mujika I, Sharma AP, Stellingwerff T. Contemporary Periodization of Altitude Training for Elite Endurance Athletes: A Narrative Review. Sports Med 2020; 49:1651-1669. [PMID: 31452130 DOI: 10.1007/s40279-019-01165-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Since the 1960s there has been an escalation in the purposeful utilization of altitude to enhance endurance athletic performance. This has been mirrored by a parallel intensification in research pursuits to elucidate hypoxia-induced adaptive mechanisms and substantiate optimal altitude protocols (e.g., hypoxic dose, duration, timing, and confounding factors such as training load periodization, health status, individual response, and nutritional considerations). The majority of the research and the field-based rationale for altitude has focused on hematological outcomes, where hypoxia causes an increased erythropoietic response resulting in augmented hemoglobin mass. Hypoxia-induced non-hematological adaptations, such as mitochondrial gene expression and enhanced muscle buffering capacity may also impact athletic performance, but research in elite endurance athletes is limited. However, despite significant scientific progress in our understanding of hypobaric hypoxia (natural altitude) and normobaric hypoxia (simulated altitude), elite endurance athletes and coaches still tend to be trailblazers at the coal face of cutting-edge altitude application to optimize individual performance, and they already implement novel altitude training interventions and progressive periodization and monitoring approaches. Published and field-based data strongly suggest that altitude training in elite endurance athletes should follow a long- and short-term periodized approach, integrating exercise training and recovery manipulation, performance peaking, adaptation monitoring, nutritional approaches, and the use of normobaric hypoxia in conjunction with terrestrial altitude. Future research should focus on the long-term effects of accumulated altitude training through repeated exposures, the interactions between altitude and other components of a periodized approach to elite athletic preparation, and the time course of non-hematological hypoxic adaptation and de-adaptation, and the potential differences in exercise-induced altitude adaptations between different modes of exercise.
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Affiliation(s)
- Iñigo Mujika
- Department of Physiology, Faculty of Medicine and Odontology, University of the Basque Country, Leioa, Basque Country, Spain. .,Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile.
| | - Avish P Sharma
- Griffith Sports Physiology and Performance, School of Allied Health Sciences, Griffith University, Gold Coast, QLD, Australia.,Triathlon Australia, Burleigh Heads, QLD, Australia
| | - Trent Stellingwerff
- Canadian Sport Institute-Pacific, Victoria, BC, Canada.,Department of Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC, Canada
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15
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Gibbons TD, Tymko MM, Thomas KN, Wilson LC, Stembridge M, Caldwell HG, Howe CA, Hoiland RL, Akerman AP, Dawkins TG, Patrician A, Coombs GB, Gasho C, Stacey BS, Ainslie PN, Cotter JD. Global REACH 2018: The influence of acute and chronic hypoxia on cerebral haemodynamics and related functional outcomes during cold and heat stress. J Physiol 2020; 598:265-284. [PMID: 31696936 DOI: 10.1113/jp278917] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 10/28/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Thermal and hypoxic stress commonly coexist in environmental, occupational and clinical settings, yet how the brain tolerates these multi-stressor environments is unknown Core cooling by 1.0°C reduced cerebral blood flow (CBF) by 20-30% and cerebral oxygen delivery (CDO2 ) by 12-19% at sea level and high altitude, whereas core heating by 1.5°C did not reliably reduce CBF or CDO2 Oxygen content in arterial blood was fully restored with acclimatisation to 4330 m, but concurrent cold stress reduced CBF and CDO2 Gross indices of cognition were not impaired by any combination of thermal and hypoxic stress despite large reductions in CDO2 Chronic hypoxia renders the brain susceptible to large reductions in oxygen delivery with concurrent cold stress, which might make monitoring core temperature more important in this context ABSTRACT: Real-world settings are composed of multiple environmental stressors, yet the majority of research in environmental physiology investigates these stressors in isolation. The brain is central in both behavioural and physiological responses to threatening stimuli and, given its tight metabolic and haemodynamic requirements, is particularly susceptible to environmental stress. We measured cerebral blood flow (CBF, duplex ultrasound), cerebral oxygen delivery (CDO2 ), oesophageal temperature, and arterial blood gases during exposure to three commonly experienced environmental stressors - heat, cold and hypoxia - in isolation, and in combination. Twelve healthy male subjects (27 ± 11 years) underwent core cooling by 1.0°C and core heating by 1.5°C in randomised order at sea level; acute hypoxia ( P ET , O 2 = 50 mm Hg) was imposed at baseline and at each thermal extreme. Core cooling and heating protocols were repeated after 16 ± 4 days residing at 4330 m to investigate any interactions with high altitude acclimatisation. Cold stress decreased CBF by 20-30% and CDO2 by 12-19% (both P < 0.01) irrespective of altitude, whereas heating did not reliably change either CBF or CDO2 (both P > 0.08). The increases in CBF with acute hypoxia during thermal stress were appropriate to maintain CDO2 at normothermic, normoxic values. Reaction time was faster and slower by 6-9% with heating and cooling, respectively (both P < 0.01), but central (brain) processes were not impaired by any combination of environmental stressors. These findings highlight the powerful influence of core cooling in reducing CDO2 . Despite these large reductions in CDO2 with cold stress, gross indices of cognition remained stable.
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Affiliation(s)
- T D Gibbons
- School of Physical Education, Sport & Exercise Science, University of Otago, 55/47 Union St W, Dunedin, 9016, New Zealand
| | - M M Tymko
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - K N Thomas
- Department of Surgical Sciences, University of Otago, 201 Great King St, Dunedin, 9016, New Zealand
| | - L C Wilson
- Department of Medicine, University of Otago, 201 Great King St, Dunedin, 9016, New Zealand
| | - M Stembridge
- Cardiff Centre for Exercise and Health, Cardiff Metropolitan University, Cyncoed Road, Cardiff, CF23 6XD, UK
| | - H G Caldwell
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - C A Howe
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - R L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - A P Akerman
- Faculty of Health Sciences, University of Ottawa, 125 University St, Ottawa, Ontario, Canada, K1N 6N5
| | - T G Dawkins
- Cardiff Centre for Exercise and Health, Cardiff Metropolitan University, Cyncoed Road, Cardiff, CF23 6XD, UK
| | - A Patrician
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - G B Coombs
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - C Gasho
- Division of Pulmonary, Critical Care, Hyperbaric and Sleep Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - B S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - P N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - J D Cotter
- School of Physical Education, Sport & Exercise Science, University of Otago, 55/47 Union St W, Dunedin, 9016, New Zealand
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16
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Levine A, Buono MJ. Rating of perceived exertion increases synergistically during prolonged exercise in a combined heat and hypoxic environment. J Therm Biol 2019; 84:99-102. [PMID: 31466796 DOI: 10.1016/j.jtherbio.2019.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to determine the cardiovascular, thermoregulatory, and perceived exertion responses during 2 h of moderate intensity exercise in a combined high heat (38 °C, 40% relative humidity) and hypoxic (15% O2) environment. Ten healthy volunteers completed 2 h of treadmill walking at 40% of maximal oxygen uptake in four different conditions, each separated by approximately 1 week: (1) control, 23 °C/20.9% O2, (2) heat, 38 °C/20.9% O2, (3) hypoxia, 23 °C/15% O2, and (4) combined heat/hypoxia, 38 °C/15% O2. Compared to the responses seen in each condition alone, heart rate (HR) and core temperature (Tcore) showed an additive increase in the combined heat and hypoxic environment after 2 h of moderate intensity exercise. The most important new finding was that the mean rating of perceived exertion (RPE) increased synergistically 3.3 units when exercising in the combined high heat and hypoxic environment, compared to 1.9 units in the heat condition alone. The results suggest that RPE is a conscious perception of effort that plays a regulatory function to ensure that the work rate remains at an intensity that can be safely sustained, rather than simply a marker of exercise intensity. Such results also support previous anecdotal reports that exercise on hot days at altitude seem unusually difficult.
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Affiliation(s)
- Ashley Levine
- School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States
| | - Michael J Buono
- Biology Department, San Diego State University, San Diego, CA, 92182, United States; School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States.
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17
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Keramidas ME, Kölegård R, Mekjavic IB, Eiken O. Interactions of mild hypothermia and hypoxia on finger vasoreactivity to local cold stress. Am J Physiol Regul Integr Comp Physiol 2019; 317:R418-R431. [PMID: 31241983 DOI: 10.1152/ajpregu.00103.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the interactive effects of mild hypothermia and hypoxia on finger vasoreactivity to local cold stress. Eight male lowlanders performed, in a counterbalanced order, a normoxic and a hypoxic (partial pressure of oxygen: ~12 kPa) hand cold provocation (consisting of a 30-min immersion in 8°C water), while immersed to the chest either in 21°C [cold trials; 0.5°C fall in rectal temperature (Trec) from individual preimmersion values], or in 35.5°C water, or while exposed to 27°C air. The duration of the trials was kept constant in each breathing condition. Physiological (Trec, skin temperature, cutaneous vascular conductance, oxygen uptake) and perceptual (thermal sensation and comfort, local pain, affective valence) reactions were monitored continually. Hypoxia accelerated the drop in Trec by ~14 min (P = 0.06, d = 0.67). In the air-exposure trials, hypoxia did not alter finger perfusion during the local cooling, whereas it impaired the finger rewarming response following the cooling (P < 0.01). During the 35.5°C immersion, the finger vasomotor tone was enhanced, especially in hypoxia (P = 0.01). Mild hypothermia aggravated finger vasoconstriction instigated by local cooling (P < 0.01), but the response did not differ between the two breathing conditions (P > 0.05). Hypoxia tended to attenuate the sensation of coldness (P = 0.10, r = 0.40) and thermal discomfort (P = 0.09, r = 0.46) in the immersed hand. Both in normoxia and hypoxia, the whole body thermal state dictates the cutaneous vasomotor reactivity to localized cold stimulus.
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Affiliation(s)
- Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Roger Kölegård
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ola Eiken
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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18
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Bradbury KE, Coffman KE, Mitchell KM, Luippold AJ, Fulco CS, Kenefick RW. Separate and combined influences of heat and hypobaric hypoxia on self-paced aerobic exercise performance. J Appl Physiol (1985) 2019; 127:513-519. [PMID: 31219777 DOI: 10.1152/japplphysiol.00023.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heat and hypobaric hypoxia independently compromise exercise performance; however, their combined impact on exercise performance has yet to be quantified. This study examined the effects of heat, hypobaric hypoxia, and the combination of these environments on self-paced cycling time trial (TT) performance. Twelve subjects [2 female, 10 male; sea level (SL) peak oxygen consumption (V̇o2peak), 41.5 ± 4.4 mL·kg-1·min-1, mean ± SD] completed 30 min of steady-state cycling exercise (50% SL V̇o2peak), followed by a 15-min self-paced TT in four environmental conditions: SL thermoneutral [SLTN; 250 m, 20°C, 30-50% relative humidity (rh)], SL hot (SLH; 250 m, 35°C, 30% rh), hypobaric hypoxia thermoneutral (HTN; 3,000 m, 20°C, 30-50% rh), and hypobaric hypoxia hot (HH; 3,000 m, 35°C, 30% rh). Performance was assessed by the total work (kJ) completed. TT performance was lower (P < 0.05) in SLH, HTN, and HH relative to SLTN (-15.4 ± 9.7, -24.1 ± 16.2, and -33.1 ± 13.4 kJ, respectively). Additionally, the total work completed in HTN and HH was lower (P < 0.05) than that in SLH. In SLH, HTN, and HH, work rate was reduced versus SLTN (P < 0.05) within the first 3 min of exercise and was consistent for the remainder of the bout. No differences (P > 0.05) existed for heart rate or Ratings of Perceived Exertion at the end of exercise among conditions. The decrease in self-paced TT performance in the heat and/or hypobaric hypoxia conditions compared with SLTN conditions resulted from a nearly immediate reduction in work rate that may have been regulated by environmentally induced changes in physiological strain and perception of effort in response to TT exercise.NEW & NOTEWORTHY This is the first known study to examine the combined effects of heat and hypobaric hypoxia on short-duration self-paced cycling time trial performance. Regardless of environmental condition, subjects utilized an even work rate for the entire duration of the time trial. The presence of both environmental stressors led to a greater performance impairment than heat or hypobaric hypoxia alone, and the performance decrement stemmed from an early reduction of work rate.
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Affiliation(s)
- Karleigh E Bradbury
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Kirsten E Coffman
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Katherine M Mitchell
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Adam J Luippold
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Charles S Fulco
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Robert W Kenefick
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
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19
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Horiuchi M, Handa-Kirihara Y, Abe D, Fukuoka Y. Combined effects of exposure to hypoxia and cool on walking economy and muscle oxygenation profiles at tibialis anterior. J Sports Sci 2019; 37:1638-1647. [PMID: 30774004 DOI: 10.1080/02640414.2019.1580130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We investigated combined effects of ambient temperature (23°C or 13°C) and fraction of inspired oxygen (21%O2 or 13%O2) on energy cost of walking (Cw: J·kg-1·km-1) and economical speed (ES). Eighteen healthy young adults (11 males, seven females) walked at seven speeds from 0.67 to 1.67 m s-1 (four min per stage). Environmental conditions were set; thermoneutral (N: 23°C) with normoxia (N: 21%O2) = NN; 23°C (N) with hypoxia (H: 13%O2) = NH; cool (C: 13°C) with 21%O2 (N) = CN, and 13°C (C) with 13%O2 (H) = CH. Muscle deoxygenation (HHb) and tissue O2 saturation (StO2) were measured at tibialis anterior. We found a significantly slower ES in NH (1.289 ± 0.091 m s-1) and CH (1.275 ± 0.099 m s-1) than in NN (1.334 ± 0.112 m s-1) and CN (1.332 ± 0.104 m s-1). Changes in HHb and StO2 were related to the ES. These results suggested that the combined effects (exposure to hypoxia and cool) is nearly equal to exposure to hypoxia and cool individually. Specifically, acute moderate hypoxia slowed the ES by approx. 4%, but acute cool environment did not affect the ES. Further, HHb and StO2 may partly account for an individual ES.
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Affiliation(s)
- Masahiro Horiuchi
- a Division of Human Environmental Science , Mt. Fuji Research Institute , Fuji-yoshdia-city , Japan
| | - Yoko Handa-Kirihara
- a Division of Human Environmental Science , Mt. Fuji Research Institute , Fuji-yoshdia-city , Japan
| | - Daijiro Abe
- b Center for Health and Sports Science , Kyushu Sangyo University , Fukuoka , Japan
| | - Yoshiyuki Fukuoka
- c Faculty of Health and Sports Science , Doshisya University , Kyoto , Japan
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20
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Haslinger S, Blank C, Morawetz D, Koller A, Dünnwald T, Berger S, Schlickum N, Schobersberger W. Effects of Recreational Ski Mountaineering on Cumulative Muscle Fatigue - A Longitudinal Trial. Front Physiol 2018; 9:1687. [PMID: 30542295 PMCID: PMC6277900 DOI: 10.3389/fphys.2018.01687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 11/09/2018] [Indexed: 01/15/2023] Open
Abstract
Sport is known to have many positive effects on mental and physical health. High-intensity exercise is considered to decrease muscle strength and induce muscle fatigue, which is associated with a higher risk of injury. In recreational alpine skiers, a decrease of eccentric peak hamstring torque, as an indication of muscle fatigue, occurs even after 1 day of skiing. The popularity of ski mountaineering is increasing enormously, but no studies are available on its effects on muscle strength. Therefore, the present study examined the consequences of ski mountaineering on muscle fatigue of the concentric/eccentric quadriceps and/or hamstrings. In addition, a possible role of myofascial foam rolling in reducing muscle fatigue was evaluated. Fifty recreational ski mountaineers (27 males, 23 females) completed five consecutive tours of ski mountaineering within 1 week. After each day of skiing, participants underwent an isokinetic muscle test assessing the concentric and eccentric muscle strength of both thighs. One group completed an additional session of myofascial foam rolling. Right and left concentric quadriceps peak torque, left hamstrings peak torque, left eccentric quadriceps peak torque, as well as right and left hamstring peak torque, were reduced after a single day of ski mountaineering (p ≤ 0.016 for all). However, no cumulative muscle fatigue was detected and we could not demonstrate any effect of myofascial foam rolling. The results show conclusively that a single day of ski mountaineering leads to a significant decrease of concentric and eccentric quadriceps and hamstring strength. Therefore, in order to improve muscle strength for the ski mountaineering season, a physical training program including concentric and eccentric methods can be recommended.
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Affiliation(s)
- Simon Haslinger
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria.,Institute for Sports Medicine, Alpine Medicine and Health Tourism, Tirol Kliniken GmbH, Tirol, Austria
| | - Cornelia Blank
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria
| | - David Morawetz
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria
| | - Arnold Koller
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, Tirol Kliniken GmbH, Tirol, Austria
| | - Tobias Dünnwald
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria
| | - Sarah Berger
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria
| | - Nico Schlickum
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria
| | - Wolfgang Schobersberger
- 1Institute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology, Tirol, Austria.,Institute for Sports Medicine, Alpine Medicine and Health Tourism, Tirol Kliniken GmbH, Tirol, Austria
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21
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Raccuglia M, Sales B, Heyde C, Havenith G, Hodder S. Clothing comfort during physical exercise - Determining the critical factors. APPLIED ERGONOMICS 2018; 73:33-41. [PMID: 30098640 DOI: 10.1016/j.apergo.2018.05.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/21/2018] [Accepted: 05/27/2018] [Indexed: 05/28/2023]
Abstract
Clothing comfort is determined by multiple material and design factors. Wetness at the skin-clothing interface mainly impacts wear comfort. The current study investigated the combined effect of fabric contact area, fabric absolute sweat content and fabric moisture saturation percentage on wetness and stickiness sensations, during exercise. Moreover, factors causing wear (dis)comfort during exercise were identified. Higher fabric saturation percentage induced greater stickiness sensation, despite lower fabric contact area and absolute sweat content (typically associated with lower stickiness). Wetness perception did not change between fabrics with different saturation percentages, contact areas and sweat contents. Therefore, fabric saturation percentage mainly affects stickiness sensation of wet fabrics, overruling the impact of fabric contact area and absolute sweat content. No overall model of wear discomfort across all data could be developed, however, models for different time points were produced, with texture and stickiness sensations being the best predictors of wear discomfort at baseline and during exercise, respectively. This suggests that the factors determining clothing (dis)comfort are dynamics and alter importance during exercise activity.
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Affiliation(s)
- Margherita Raccuglia
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK
| | - Benjamin Sales
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK
| | | | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK.
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22
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Raccuglia M, Heyde C, Lloyd A, Ruiz D, Hodder S, Havenith G. Anchoring biases affect repeated scores of thermal, moisture, tactile and comfort sensations in transient conditions. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2018; 62:1945-1954. [PMID: 30083800 PMCID: PMC6182318 DOI: 10.1007/s00484-018-1595-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/13/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
In this study, we addressed potential biases which can occur when sensorial scores of temperature, wetness and discomfort are repeatedly reported, in transient exercise conditions. We pointed out that, when repeatedly reported, previous sensorial scores can be set by the participants as reference values and the subsequent score may be given based on the previous point of reference, the latter phenomenon leading to a bias which we defined as 'anchoring bias'. Indeed, the findings shown that subsequent sensorial scores are prone to anchoring biases and that the bias consisted in a systematically higher magnitude of sensation as compared to when reported a single time only. As such, the study allowed recognition, quantification and mitigation of the identified bias which can improve the methodological rigour of research studies involving assessments of sensorial data in transient conditions.
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Affiliation(s)
- Margherita Raccuglia
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
- Adidas FUTURE Sport Science, Herzogenaurach, Germany.
| | | | - Alex Lloyd
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Daniel Ruiz
- Adidas FUTURE Sport Science, Herzogenaurach, Germany
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
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23
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Alhammoud M, Morel B, Girard O, Racinais S, Sevrez V, Germain A, Chamu T, Hautier C. Hypoxia and Fatigue Impair Rapid Torque Development of Knee Extensors in Elite Alpine Skiers. Front Physiol 2018; 9:962. [PMID: 30140231 PMCID: PMC6094991 DOI: 10.3389/fphys.2018.00962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 06/29/2018] [Indexed: 01/20/2023] Open
Abstract
This study examined the effects of acute hypoxia on maximal and explosive torque and fatigability in knee extensors of skiers. Twenty-two elite male alpine skiers performed 35 maximal, repeated isokinetic knee extensions at 180°s-1 (total exercise duration 61.25 s) in normoxia (NOR, FiO2 0.21) and normobaric hypoxia (HYP, FiO2 0.13) in a randomized, single-blind design. Peak torque and rate of torque development (RTD) from 0 to 100 ms and associated Vastus Lateralis peak EMG activity and rate of EMG rise (RER) were determined for each contraction. Relative changes in deoxyhemoglobin concentration of the VL muscle were monitored by near-infrared spectroscopy. Peak torque and peak EMG activity did not differ between conditions and decreased similarly with fatigue (p < 0.001), with peak torque decreasing continuously but EMG activity decreasing significantly after 30 contractions only. Compared to NOR, RTD, and RER values were lower in HYP during the first 12 and 9 contractions, respectively (both p < 0.05). Deoxyhemoglobin concentration during the last five contractions was higher in HYP than NOR (p = 0.050) but the delta between maximal and minimal deoxyhemoglobin for each contraction was similar in HYP and NOR suggesting a similar muscle O2 utilization. Post-exercise heart rate (138 ± 24 bpm) and blood lactate concentration (5.8 ± 3.1 mmol.l-1) did not differ between conditions. Arterial oxygen saturation was significantly lower (84 ± 4 vs. 98 ± 1%, p < 0.001) and ratings of perceived exertion higher (6 ± 1 vs. 5 ± 1, p < 0.001) in HYP than NOR. In summary, hypoxia limits RTD via a decrease in neural drive in elite alpine skiers undertaking maximal repeated isokinetic knee extensions, but the effect of hypoxic exposure is negated as fatigue develops. Isokinetic testing protocols for elite alpine skiers should incorporate RTD and RER measurements as they display a higher sensitivity than peak torque and EMG activity.
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Affiliation(s)
- Marine Alhammoud
- Inter-university Laboratory of Human Movement Biology (EA 7424), Claude Bernard University Lyon 1, Lyon, France.,French Ski Federation, Annecy, France
| | - Baptiste Morel
- Laboratory "Movement, Interactions, Performance" (EA 4334), Le Mans University, Le Mans, France
| | - Olivier Girard
- School of Psychology and Exercise Science, Murdoch University, Perth, WA, Australia.,Athlete Health and Performance Research Centre, Aspetar Orthopedic and Sports Medicine Hospital, Doha, Qatar
| | - Sebastien Racinais
- Athlete Health and Performance Research Centre, Aspetar Orthopedic and Sports Medicine Hospital, Doha, Qatar.,Laboratory Sport, Expertise and Performance, French Institute of Sport (INSEP), Paris, France
| | - Violaine Sevrez
- French National Center for Scientific Research, Institute of Movement Sciences, Aix-Marseille University, Marseille, France
| | | | - Thomas Chamu
- Orthopedic and Sports Medicine Hospital La Sauvegarde, Lyon, France
| | - Christophe Hautier
- Inter-university Laboratory of Human Movement Biology (EA 7424), Claude Bernard University Lyon 1, Lyon, France
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24
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Pereira VH, Gobatto CA, Lewis TG, Ribeiro LFP, Beck WR, dos Reis IGM, Sousa FAB, Manchado-Gobatto FB. Computational and Complex Network Modeling for Analysis of Sprinter Athletes' Performance in Track Field Tests. Front Physiol 2018; 9:843. [PMID: 30034346 PMCID: PMC6043640 DOI: 10.3389/fphys.2018.00843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/14/2018] [Indexed: 11/17/2022] Open
Abstract
Sports and exercise today are popular for both amateurs and athletes. However, we continue to seek the best ways to analyze best athlete performances and develop specific tools that may help scientists and people in general to analyze athletic achievement. Standard statistics and cause-and-effect research, when applied in isolation, typically do not answer most scientific questions. The human body is a complex holistic system exchanging data during activities, as has been shown in the emerging field of network physiology. However, the literature lacks studies regarding sports performance, running, exercise, and more specifically, sprinter athletes analyzed mathematically through complex network modeling. Here, we propose complex models to jointly analyze distinct tests and variables from track sprinter athletes in an untargeted manner. Through complex propositions, we have incorporated mathematical and computational modeling to analyze anthropometric, biomechanics, and physiological interactions in running exercise conditions. Exercise testing associated with complex network and mathematical outputs make it possible to identify which responses may be critical during running. The physiological basis, aerobic, and biomechanics variables together may play a crucial role in performance. Coaches, trainers, and runners can focus on improving specific outputs that together help toward individuals' goals. Moreover, our type of analysis can inspire the study and analysis of other complex sport scenarios.
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Affiliation(s)
- Vanessa H. Pereira
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Claudio A. Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Theodore G. Lewis
- Center for Homeland Defense and Security, Naval Postgraduate School, Monterey, CA, United States
| | - Luiz F. P. Ribeiro
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Wladimir R. Beck
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Ivan G. M. dos Reis
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Filipe A. B. Sousa
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - Fúlvia B. Manchado-Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, Brazil
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Lloyd A, Picton L, Raccuglia M, Hodder S, Havenith G. Localized and systemic variations in central motor drive at different local skin and muscle temperatures. Am J Physiol Regul Integr Comp Physiol 2017; 313:R219-R228. [PMID: 28592458 DOI: 10.1152/ajpregu.00055.2017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/12/2017] [Accepted: 06/05/2017] [Indexed: 11/22/2022]
Abstract
This study investigated the ability to sustain quadriceps central motor drive while subjected to localized heat and metaboreceptive feedback from the contralateral leg. Eight active males each completed two counter-balanced trials, in which muscle temperature (Tm) of a single-leg (TEMP-LEG) was altered to 29.4°C (COOL) or 37.6°C (WARM), while the contralateral leg (CL-LEG) remained thermoneutral: 35.3°C and 35.2°C Tm in COOL and WARM, respectively. To activate metaboreceptive feedback, participants first performed one 120-s isometric maximal voluntary contraction (MVC) of the knee extensors in the TEMP-LEG, immediately followed by postexercise muscle ischemia (PEMI) via femoral blood flow occlusion. To assess central motor drive of a remote muscle group immediately following PEMI, another 120-s MVC was subsequently performed in the CL-LEG. Voluntary muscle activation (VA) was assessed using the twitch interpolation method. Perceived mental effort and limb discomfort were also recorded. In a cooled muscle, a significant increase in mean force output and mean VA (force, P < 0.001; VA, P < 0.05), as well as a significant decrease in limb discomfort (P < 0.05) occurred during the sustained MVC in the TEMP-LEG. However, no differences between Tm were observed in mean force output, mean VA, or limb discomfort during the sustained MVC in the CL-LEG (force, P = 0.33; VA, P > 0.68; and limb discomfort, P = 0.73). The present findings suggest that elevated local skin temperature and Tm can increase limb discomfort and decrease central motor drive, but this does not limit systemic motor activation of a thermoneutral muscle group.
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Affiliation(s)
- Alex Lloyd
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
| | - Lewis Picton
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
| | - Margherita Raccuglia
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
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Separate and combined effects of exposure to heat stress and mental fatigue on endurance exercise capacity in the heat. Eur J Appl Physiol 2016; 117:119-129. [PMID: 27864637 DOI: 10.1007/s00421-016-3504-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/11/2016] [Indexed: 12/25/2022]
Abstract
PURPOSE This study investigated the effects of exposure to pre-exercise heat stress and mental fatigue on endurance exercise capacity in a hot environment. METHODS Eight volunteers completed four cycle exercise trials at 80% maximum oxygen uptake until exhaustion in an environmental chamber maintained at 30 °C and 50% relative humidity. The four trials required them to complete a 90 min pre-exercise routine of either a seated rest (CON), a prolonged demanding cognitive task to induce mental fatigue (MF), warm water immersion at 40 °C during the last 30 min to induce increasing core temperature (WI), or a prolonged demanding cognitive task and warm water immersion at 40 °C during the last 30 min (MF + WI). RESULTS Core temperature when starting exercise was higher following warm water immersion (~38 °C; WI and MF + WI) than with no water immersion (~36.8 °C; CON and MF, P < 0.001). Self-reported mental fatigue when commencing exercise was higher following cognitive task (MF and MF + WI) than with no cognitive task (CON and WI; P < 0.05). Exercise time to exhaustion was reduced by warm water immersion (P < 0.001) and cognitive task (P < 0.05). Compared with CON (18 ± 7 min), exercise duration reduced 0.8, 26.6 and 46.3% in MF (17 ± 7 min), WI (12 ± 5 min) and MF + WI (9 ± 3 min), respectively. CONCLUSIONS This study demonstrates that endurance exercise capacity in a hot environment is impaired by either exposure to pre-exercise heat stress or mental fatigue, and this response is synergistically increased during combined exposure to them.
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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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No M, Kwak HB. Effects of environmental temperature on physiological responses during submaximal and maximal exercises in soccer players. Integr Med Res 2016; 5:216-222. [PMID: 28462121 PMCID: PMC5390419 DOI: 10.1016/j.imr.2016.06.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 05/29/2016] [Accepted: 06/09/2016] [Indexed: 11/24/2022] Open
Abstract
Background Although thermoregulation is effective in regulating body temperature under normal conditions, exercise or physical activity in extreme cold or heat exerts heavy stress on the mechanisms that regulate body temperature. The purpose of this study was to investigate the effects of environmental temperature on physiological responses and endurance exercise capacity during submaximal and maximal exercises in healthy adults. Methods Nine male soccer players participated in this study. In this study, three environmental temperatures were set at 10 ± 1°C, 22 ± 1°C, and 35 ± 1°C with the same humidity (60 ± 10%). The participants cycled for 20 minutes at 60% maximum oxygen uptake (60% VO2max), and then exercise intensity was increased at a rate of 0.5 kp/2 min until exhaustion at three different environmental conditions. Results Oxygen uptake and heart rate were lower in a moderate environment (22 ± 1°C) than in a cool (10 ± 1°C) or hot (35 ± 1°C) environment at rest and during submaximal exercise, and were higher during maximal exercise (p < 0.05). Minute ventilation was lower at 22 ± 1°C than at 10 ± 1°C or 35 ± 1°C at rest and during submaximal exercise, and no significant differences were observed in minute ventilation during maximal exercise (p < 0.05). Blood lactate concentrations were lower at 22 ± 1 °C than at 10 ± 1°C or 35 ± 1°C at rest and during submaximal exercise, and were higher during maximal exercise (p < 0.05). Time to exhaustion during exercise was longer at 22 ± 1°C than at 10 ± 1°C or 35 ± 1°C (p < 0.05). Conclusion It is concluded that physiological responses and endurance exercise capacity are impaired under cool or hot conditions compared with moderate conditions, suggesting that environmental temperature conditions play an important role for exercise performance.
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Affiliation(s)
- MiHyun No
- Department of Kinesiology, Inha University, Incheon, Republic of Korea
| | - Hyo-Bum Kwak
- Department of Kinesiology, Inha University, Incheon, Republic of Korea
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Lloyd A, Havenith G. Interactions in human performance: An individual and combined stressors approach. Temperature (Austin) 2016; 3:514-517. [PMID: 28090553 PMCID: PMC5198808 DOI: 10.1080/23328940.2016.1189991] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Alex Lloyd
- Environmental Ergonomics Research Center, Design School Loughborough University , Loughborough, UK
| | - George Havenith
- Environmental Ergonomics Research Center, Design School Loughborough University , Loughborough, UK
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