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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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Mornas A, Brocherie F, Guilhem G, Guillotel A, LE Garrec S, Gouwy R, Gennisson JL, Beuve S, Racinais S. Active Heat Acclimation Does Not Alter Muscle-Tendon Unit Properties. Med Sci Sports Exerc 2023; 55:1076-1086. [PMID: 36719653 DOI: 10.1249/mss.0000000000003129] [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: 02/01/2023]
Abstract
PURPOSE Heat acclimation (HA) is recommended before competing in hot and humid conditions. HA has also been recently suggested to increase muscle strength, but its effects on human's muscle and tendon mechanical properties are not yet fully understood. This study investigated the effect of active HA on gastrocnemius medialis (GM) muscle-tendon properties. METHODS Thirty recreationally active participants performed 13 low-intensity cycling sessions, distributed over a 17-d period in hot (HA = ~38°C, ~58% relative humidity; n = 15) or in temperate environment (CON = ~23°C, ~35% relative humidity; n = 15). Mechanical data and high-frame rate ultrasound images were collected during electrically evoked and voluntary contractions pre- and postintervention. Shear modulus was measured at rest in GM, and vertical jump performance was assessed. RESULTS Core temperature decreased from the first to the last session in HA (-0.4°C ± 0.3°C; P = 0.015), while sweat rate increased (+0.4 ± 0.3 L·h -1 ; P = 0.010), suggesting effective HA, whereas no changes were observed in CON (both P ≥ 0.877). Heart rate was higher in HA versus CON and decreased throughout intervention in groups (both P ≤ 0.008), without an interaction effect ( P = 0.733). Muscle-tendon unit properties (i.e., maximal and explosive isometric torque production, contractile properties, voluntary activation, joint and fascicular force-velocity relationship, passive muscle, and active tendon stiffness) and vertical jump performance did not show training ( P ≥ 0.067) or group-training interaction ( P ≥ 0.232) effects. CONCLUSIONS Effective active HA does not alter muscle-tendon properties. Preparing hot and humid conditions with active HA can be envisaged in all sporting disciplines without the risk of impairing muscle performance.
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Affiliation(s)
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | - Gaël Guilhem
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | - Arthur Guillotel
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | | | | | - Jean-Luc Gennisson
- Laboratoire d'Imagerie Biomédicale Multimodale (BioMaps), CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Université Paris-Saclay, Orsay, FRANCE
| | - Steve Beuve
- Laboratoire d'Imagerie Biomédicale Multimodale (BioMaps), CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Université Paris-Saclay, Orsay, FRANCE
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3
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Gordon RJFH, Moss JN, Castelli F, Reeve T, Diss CE, Tyler CJ, Tillin NA. Heat acclimation reduces the effects of whole-body hyperthermia on knee-extensor relaxation rate, but does not affect voluntary torque production. Eur J Appl Physiol 2023; 123:1067-1080. [PMID: 36637508 PMCID: PMC10119217 DOI: 10.1007/s00421-022-05127-7] [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: 08/05/2022] [Accepted: 12/23/2022] [Indexed: 01/14/2023]
Abstract
PURPOSE This study investigated the effects of acute hyperthermia and heat acclimation (HA) on maximal and rapid voluntary torque production, and their neuromuscular determinants. METHODS Ten participants completed 10 days of isothermic HA (50 °C, 50% rh) and had their knee-extensor neuromuscular function assessed in normothermic and hyperthermic conditions, pre-, after 5 and after 10 days of HA. Electrically evoked twitch and octet (300 Hz) contractions were delivered at rest. Maximum voluntary torque (MVT), surface electromyography (EMG) normalised to maximal M-wave, and voluntary activation (VA) were assessed during brief maximal isometric voluntary contractions. Rate of torque development (RTD) and normalised EMG were measured during rapid voluntary contractions. RESULTS Acute hyperthermia reduced neural drive (EMG at MVT and during rapid voluntary contractions; P < 0.05), increased evoked torques (P < 0.05), and shortened contraction and relaxation rates (P < 0.05). HA lowered resting rectal temperature and heart rate after 10 days (P < 0.05), and increased sweating rate after 5 and 10 days (P < 0.05), no differences were observed between 5 and 10 days. The hyperthermia-induced reduction in twitch half-relaxation was attenuated after 5 and 10 days of HA, but there were no other effects on neuromuscular function either in normothermic or hyperthermic conditions. CONCLUSION HA-induced favourable adaptations to the heat after 5 and 10 days of exposure, but there was no measurable benefit on voluntary neuromuscular function in normothermic or hyperthermic conditions. HA did reduce the hyperthermic-induced reduction in twitch half-relaxation time, which may benefit twitch force summation and thus help preserve voluntary torque in hot environmental conditions.
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Affiliation(s)
- Ralph Joseph Frederick Hills Gordon
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK. .,Faculty of Science and Engineering, School of Psychology & Sport Science, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK.
| | - Jodie Natasha Moss
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
| | - Federico Castelli
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
| | - Thomas Reeve
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
| | - Ceri Elen Diss
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
| | - Christopher James Tyler
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
| | - Neale Anthony Tillin
- School of Life and Health Life Sciences, University of Roehampton, Holybourne Avenue, London, SW15 4JD, England, UK
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Fenemor S, Mills B, Sella F, Gill N, Driller M, Black K, Casadio J, Beaven C. Evaluation of an off-feet heat response test for elite rugby sevens athletes. Sci Sports 2022. [DOI: 10.1016/j.scispo.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Alkemade P, Gerrett N, Daanen HAM, Eijsvogels TMH, Janssen TWJ, Keaney LC. Heat acclimation does not negatively affect salivary immunoglobulin-A and self-reported illness symptoms and wellness in recreational athletes. Temperature (Austin) 2022; 9:331-343. [PMID: 36339091 PMCID: PMC9629114 DOI: 10.1080/23328940.2022.2088029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heat acclimation (HA) protocols repeatedly expose individuals to heat stress. As HA is typically performed close to the pinnacle event, it is essential that the protocol does not compromise immune status, health, or wellbeing. The purpose of this study was to examine the effect of HA on resting salivary immunoglobulin-A (s-IgA) and salivary cortisol (s-cortisol), self-reported upper-respiratory tract symptoms, and self-reported wellness parameters. Seventeen participants (peak oxygen uptake 53.2 ± 9.0 mL·kg−1·min−1) completed a 10-day controlled-hyperthermia HA protocol, and a heat stress test both before (HST1) and after (HST2) HA (33°C, 65% relative humidity). Resting saliva samples were collected at HST1, day 3 and 7 of the HA protocol, HST2, and at 5 ± 1 days post-HA. Upper-respiratory tract symptom data were collected weekly from one week prior to HA until three weeks post HA, and wellness ratings were reported daily throughout HA. HA successfully induced physiological adaptations, with a lower end-exercise rectal temperature and heart rate and higher whole-body sweat rate at HST2 compared to HST1. In contrast, resting saliva flow rate, s-IgA concentration, s-cortisol concentration, and s-cortisol secretion rate remained unchanged (n = 11–14, P = 0.10–0.48). Resting s-IgA secretion rate increased by 39% from HST1 to HST2 (n = 14, P = 0.03). No changes were observed in self-reported upper respiratory tract symptoms and wellness ratings. In conclusion, controlled-hyperthermia HA did not negatively affect resting s-IgA and s-cortisol, self-reported upper-respiratory tract symptoms, and self-reported wellness parameters in recreational athletes.
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Affiliation(s)
- Puck Alkemade
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Nicola Gerrett
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Gentherm, Northville, MI, USA
| | - Hein A. M. Daanen
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Thijs M. H. Eijsvogels
- Radboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas W. J. Janssen
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Lauren C. Keaney
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
- Defence Technology Agency, New Zealand Defence Force, Auckland, New Zealand
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6
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Ramos JAP, Brade CJ, Ducker KJ, Landers GJ, Girard O. The Internal-to-External Load Ratio: A Tool to Determine the Efficacy of Heat Acclimation/Acclimatization Using Self-Paced Exercise. Front Sports Act Living 2022; 3:830378. [PMID: 35088049 PMCID: PMC8787152 DOI: 10.3389/fspor.2021.830378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/17/2021] [Indexed: 11/30/2022] Open
Affiliation(s)
- Julian Andro P. Ramos
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
- *Correspondence: Julian Andro P. Ramos
| | - Carly J. Brade
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
| | - Kagan J. Ducker
- Curtin School of Allied Health, Curtin University, Bentley, WA, Australia
| | - Grant J. Landers
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA, Australia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA, Australia
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7
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Osborne JO, Stewart IB, Borg DN, Beagley KW, Buhmann RL, Minett GM. Short-term heat acclimation preserves knee extensor torque but does not improve 20 km self-paced cycling performance in the heat. Eur J Appl Physiol 2021; 121:2761-2772. [PMID: 34148124 PMCID: PMC8416835 DOI: 10.1007/s00421-021-04744-y] [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: 03/23/2021] [Accepted: 06/10/2021] [Indexed: 01/16/2023]
Abstract
Purpose This study investigated the effect of 5 days of heat acclimation training on neuromuscular function, intestinal damage, and 20 km cycling (20TT) performance in the heat. Methods Eight recreationally trained males completed two 5-day training blocks (cycling 60 min day−1 at 50% peak power output) in a counter-balanced, cross-over design, with a 20TT completed before and after each block. Training was conducted in hot (HA: 34.9 ± 0.7 °C, 53 ± 4% relative humidity) or temperate (CON: 22.2 ± 2.6 °C, 65 ± 8% relative humidity) environment. All 20TTs were completed in the heat (35.1 ± 0.5 °C, 51 ± 4% relative humidity). Neuromuscular assessment of knee extensors (5 × 5 s maximum voluntary contraction; MVC) was completed before and after each 20TT and on the first and last days of each training block. Results MVC torque was statistically higher after 5 days of HA training compared to CON (mean difference = 14 N m [95% confidence interval; 6, 23]; p < 0.001; d = 0.77). However, 20TT performance after 5 days of HA training was not statistically different to CON, with a between-conditions mean difference in the completion time of 68 s [95% confidence interval; − 9, 145] (p = 0.076; d = 0.35). Conclusion Short-term heat acclimation training may increase knee extensor strength without changes in central fatigue or intestinal damage. Nevertheless, it is insufficient to improve 20 km self-paced cycling performance in the heat compared to workload-matched training in a temperate environment. These data suggest that recreationally trained athletes gain no worthwhile performance advantage from short-term heat-training before competing in the heat. Supplementary Information The online version contains supplementary material available at 10.1007/s00421-021-04744-y.
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Affiliation(s)
- John O Osborne
- School of Sport Sciences, UiT The Arctic University of Norway, Tromsø, Norway. .,School of Exercise and Nutrition Sciences, Queensland University of Technology (QUT), Brisbane, Australia. .,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.
| | - Ian B Stewart
- School of Exercise and Nutrition Sciences, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | - David N Borg
- School of Exercise and Nutrition Sciences, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,The Hopkins Centre, Menzies Health Institute Queensland, Griffith University, Brisbane, Australia
| | - Kenneth W Beagley
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia
| | - Robert L Buhmann
- School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Australia
| | - Geoffrey M Minett
- School of Exercise and Nutrition Sciences, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
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8
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Gale RM, Etxebarria N, Pumpa KL, Pyne DB. Cycling-based repeat sprint training in the heat enhances running performance in team sport players. Eur J Sport Sci 2021; 21:695-704. [PMID: 32316870 DOI: 10.1080/17461391.2020.1759696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Applying heat training interventions in a team sports setting remains challenging. This study investigated the effects of integrating short-term, repeat sprint heat training with passive heat exposure on running performance and general conditioning in team sport players. Thirty male club-level Australian Football players were assigned randomly to: Passive + Active Heat (PAH; n = 10), Active Heat (AH; n = 10) or Control (CON; n = 10) to complete 6 × 40 min high-intensity cycling training sessions over 12 days in 35°C (PAH and AH) or 18°C (CON), 50% RH in parallel with mid-season sports-specific training and games. Players in PAH were exposed to 20 min pre-exercise passive heat. Physiological adaptation and running capacity were assessed via a treadmill submaximal heat stress test followed by a time-to-exhaustion run in 35°C, 50% RH. Running capacity increased by 26% ± 8% PAH (0.88, ±0.23; standardised mean, ± 90% confidence limits), 29% ± 12% AH (1.23, ±0.45) and 10% ± 11% CON (0.45, ±0.48) compared with baseline. Both PAH (0.52, ±0.42; standardised mean, ± 90% confidence limits) and AH (0.35, ±0.57) conditions yielded a greater improvement in running capacity than CON. Physiological and perceptual measures remained relatively unchanged between baseline and post-intervention heat stress tests, within and between conditions. When thermal adaptation is not a direct priority, short-term, repeat effort high-intensity cycling in hot conditions combined with sports-specific training can further enhance running performance in team sport players. Six heat exposures across 12-days should improve running performance while minimising lower limb load and cumulative fatigue for team sports players.
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Affiliation(s)
- Rachel M Gale
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
| | - Naroa Etxebarria
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
- Discipline of Exercise and Sport Sciences, Faculty of Health, University of Canberra, Bruce, Australia
| | - Kate L Pumpa
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
- Discipline of Exercise and Sport Sciences, Faculty of Health, University of Canberra, Bruce, Australia
| | - David B Pyne
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
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9
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Roussey G, Bernard T, Fontanari P, Louis J. Heat acclimation training with intermittent and self-regulated intensity may be used as an alternative to traditional steady state and power-regulated intensity in endurance cyclists. J Therm Biol 2021; 98:102935. [PMID: 34016357 DOI: 10.1016/j.jtherbio.2021.102935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 03/01/2021] [Accepted: 03/29/2021] [Indexed: 11/26/2022]
Abstract
The study aimed to determine the effects of self-regulated and variable intensities sustained during short-term heat acclimation training on cycling performance. Seventeen competitive-level male athletes performed a 20-km cycling time trial before (TT-PRE), immediately after (TT-POST1) and one week after (TT-POST2) a 5-day acclimation training program, including either RPE-regulated intermittent (HA-HIT, N = 9) or fixed and low-intensity (HA-LOW, N = 8) training sessions in the heat (39 °C; 40% relative humidity). Total training volume was 23% lower in HA-HIT compared to HA-LOW. Physiological responses were evaluated during a 40-min fixed-RPE cycling exercise performed before (HST-PRE) and immediately after (HST-POST) heat acclimation. All participants in HA-LOW group tended to improve mean power output from TT-PRE to TT-POST1 (+8.1 ± 5.2%; ES = 0.55 ± 0.23), as well as eight of the nine athletes in HA-HIT group (+4.3 ± 2.0%; ES = 0.29 ± 0.31) without difference between groups, but TT-POST2 results showed that improvements were dissipated one week after. Similar improvements in thermal sensation and lower elevations of core temperature in HST-POST following HA-LOW and HA-HIT training protocols suggest that high intensity and RPE regulated bouts could be an efficient strategy for short term heat acclimation protocols, for example prior to the competition. Furthermore, the modest impact of lowered thermal sensation on cycling performance confirms that perceptual responses of acclimated athletes are dissociated from physiological stress when exercising in the heat.
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Affiliation(s)
- Gilles Roussey
- Laboratoire Motricité Humaine, Education, Sport, Santé (LAMHESS), Université Côte d'Azur, Nice, France
| | - Thierry Bernard
- Laboratoire Motricité Humaine, Education, Sport, Santé (LAMHESS), Université Côte d'Azur, Nice, France
| | - Pierre Fontanari
- Laboratoire Motricité Humaine, Education, Sport, Santé (LAMHESS), Université Côte d'Azur, Nice, France
| | - Julien Louis
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Liverpool, Byrom Street, L3 3AF, United Kingdom.
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Callovini A, Fornasiero A, Savoldelli A, Stella F, Low DA, Pellegrini B, Schena F, Bortolan L. Effects of three-exercise sessions in the heat on endurance cycling performance. J Therm Biol 2021; 98:102925. [PMID: 34016347 DOI: 10.1016/j.jtherbio.2021.102925] [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: 10/26/2020] [Revised: 03/22/2021] [Accepted: 03/27/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the effects of a very short-term acclimation protocol (VSTAP) on performance, physiological and perceptual responses to exercise in the heat. METHODS 12 trained male cyclists (age 31.2 ± 7; weight 71.3 ± 7 kg, VO2max: 58.4 ± 3.7 mL/kg/min) randomly performed two Time to Exhaustion Tests (TTE) at 75% of normothermic peak power output (PPO), one in normothermia (N,18°C-50% RH) and one in the heat (H,35°C-50% RH), before and after a VSTAP intervention, consisting of 3 days-90 min exercise (10min at 30% of PPO+80 min at 50% of PPO) in H (≈4.5h of heat exposure). Performance time of TTEs and physiological and perceptual variables of both TTEs and training sessions (T1, T2 and T3) were evaluated. RESULTS Magnitude Based Inferences (MBI) revealed 92/6/1% and 62/27/11% chances of positive/trivial/negative effects of VSTAP of improving performance in H (+17%) and in N (+9%), respectively. Heart Rate (HR) decreased from T1 to T3 (p < 0.001) and T2 to T3 (p < 0.001), whereas Tympanic Temperature (TyT) decreased from T1 to T2 (p = 0.047) and from T1 to T3 (p = 0.007). Furthermore, despite the increased tolerance to target Power Output (PO) throughout training sessions, RPE decreased from T1 to T3 (p = 0.032). CONCLUSIONS The VSTAP determined meaningful physiological (i.e. decreased HR and TyT) and perceptual (i.e. decreased RPE) adaptations to submaximal exercise. Furthermore, showing good chances to improve performance in the heat, it represents a valid acclimation strategy to be implemented when no longer acclimation period is possible. Finally, no cross-over effect of the VSTAP on performance in temperate conditions was detected.
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Affiliation(s)
- Alexa 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.
| | - Alessandro Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Aldo Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Federico Stella
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy.
| | - David A Low
- Liverpool John Moores University, Research Institute for Sport and Exercise Sciences (RISES), Liverpool, United Kingdom.
| | - Barbara Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Federico 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.
| | - Lorenzo Bortolan
- 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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11
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Ashworth ET, Cotter JD, Kilding AE. Methods for improving thermal tolerance in military personnel prior to deployment. Mil Med Res 2020; 7:58. [PMID: 33248459 PMCID: PMC7700709 DOI: 10.1186/s40779-020-00287-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
Acute exposure to heat, such as that experienced by people arriving into a hotter or more humid environment, can compromise physical and cognitive performance as well as health. In military contexts heat stress is exacerbated by the combination of protective clothing, carried loads, and unique activity profiles, making them susceptible to heat illnesses. As the operational environment is dynamic and unpredictable, strategies to minimize the effects of heat should be planned and conducted prior to deployment. This review explores how heat acclimation (HA) prior to deployment may attenuate the effects of heat by initiating physiological and behavioural adaptations to more efficiently and effectively protect thermal homeostasis, thereby improving performance and reducing heat illness risk. HA usually requires access to heat chamber facilities and takes weeks to conduct, which can often make it impractical and infeasible, especially if there are other training requirements and expectations. Recent research in athletic populations has produced protocols that are more feasible and accessible by reducing the time taken to induce adaptations, as well as exploring new methods such as passive HA. These protocols use shorter HA periods or minimise additional training requirements respectively, while still invoking key physiological adaptations, such as lowered core temperature, reduced heart rate and increased sweat rate at a given intensity. For deployments of special units at short notice (< 1 day) it might be optimal to use heat re-acclimation to maintain an elevated baseline of heat tolerance for long periods in anticipation of such an event. Methods practical for military groups are yet to be fully understood, therefore further investigation into the effectiveness of HA methods is required to establish the most effective and feasible approach to implement them within military groups.
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Affiliation(s)
- Edward Tom Ashworth
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, 17 Antares Place, Rosedale, Auckland, 0632 New Zealand
| | - James David Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, Otago 9016 New Zealand
| | - Andrew Edward Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, 17 Antares Place, Rosedale, Auckland, 0632 New Zealand
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12
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Lim CL. Fundamental Concepts of Human Thermoregulation and Adaptation to Heat: A Review in the Context of Global Warming. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E7795. [PMID: 33114437 PMCID: PMC7662600 DOI: 10.3390/ijerph17217795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022]
Abstract
The international community has recognized global warming as an impending catastrophe that poses significant threat to life on earth. In response, the signatories of the Paris Agreement (2015) have committed to limit the increase in global mean temperature to < 1.5 °C from pre-industry period, which is defined as 1950-1890. Considering that the protection of human life is a central focus in the Paris Agreement, the naturally endowed properties of the human body to protect itself from environmental extremes should form the core of an integrated and multifaceted solution against global warming. Scholars believe that heat and thermoregulation played important roles in the evolution of life and continue to be a central mechanism that allows humans to explore, labor and live in extreme conditions. However, the international effort against global warming has focused primarily on protecting the environment and on the reduction of greenhouse gases by changing human behavior, industrial practices and government policies, with limited consideration given to the nature and design of the human thermoregulatory system. Global warming is projected to challenge the limits of human thermoregulation, which can be enhanced by complementing innate human thermo-plasticity with the appropriate behavioral changes and technological innovations. Therefore, the primary aim of this review is to discuss the fundamental concepts and physiology of human thermoregulation as the underlying bases for human adaptation to global warming. Potential strategies to extend human tolerance against environmental heat through behavioral adaptations and technological innovations will also be discussed. An important behavioral adaptation postulated by this review is that sleep/wake cycles would gravitate towards a sub-nocturnal pattern, especially for outdoor activities, to avoid the heat in the day. Technologically, the current concept of air conditioning the space in the room would likely steer towards the concept of targeted body surface cooling. The current review was conducted using materials that were derived from PubMed search engine and the personal library of the author. The PubMed search was conducted using combinations of keywords that are related to the theme and topics in the respective sections of the review. The final set of articles selected were considered "state of the art," based on their contributions to the strength of scientific evidence and novelty in the domain knowledge on human thermoregulation and global warming.
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Affiliation(s)
- Chin Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
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13
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Ko Y, Kang J, Seol SH, Lee JY. Effectiveness of skin-heating using a water-perfused suit as passive and post-exercise heat acclimation strategies. J Therm Biol 2020; 93:102703. [PMID: 33077124 DOI: 10.1016/j.jtherbio.2020.102703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 11/26/2022]
Abstract
The purpose of the present study was to evaluate the effectiveness of passive and post-exercise heat acclimation strategies through directly heating the skin with a water-perfused suit. Nineteen young males participated in the heat acclimation (HA) protocols for 10 days, which were conducted at an air temperature of 33oC with 60%RH. The exercise-only condition (N = 6) conducted 1-h treadmill walking (6 km·h-1) followed by 1-h rest. The post-exercise passive-heating condition (N = 6) wore the suit (inflow water temperature 44.2oC) for 1-h after 1-h walking. The passive-heating condition (N = 7) donned the suit for 2 h. Heat tolerance tests (leg immersion in 42oC water for 60 min) were conducted before and after the training to evaluate changes due to the 10-day intervention. Reflecting that suit-wearing for 10 days as both passive and post-exercise HA strategies can effectively induce adaptive changes, significant interaction effects appeared in: increase or decrease in mean skin temperature (P < 0.05) and elevation in whole-body sweat rate (P < 0.05). Reduction in rectal temperature (P < 0.05) and blood pressure (P < 0.05) were found most prominently in the passive-heating condition. These results indicate that this new method of heat acclimation training, donning a skin-heating water-perfused suit, can generate thermoregulatory benefits. The passive HA intervention could be applied to individuals for whom doing exercise regularly are not feasible.
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Affiliation(s)
- Yelin Ko
- College of Human Ecology, Seoul National University, South Korea
| | - Juho Kang
- College of Human Ecology, Seoul National University, South Korea; Department of Physical Education, Seoul National University, South Korea
| | - Seon-Hong Seol
- College of Human Ecology, Seoul National University, South Korea
| | - Joo-Young Lee
- College of Human Ecology, Seoul National University, South Korea; Research Institute of Human Ecology, Seoul National University, South Korea.
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14
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Choo HC, Peiffer JJ, Pang JWJ, Tan FHY, Aziz AR, Ihsan M, Lee JKW, Abbiss CR. Effect of regular precooling on adaptation to training in the heat. Eur J Appl Physiol 2020; 120:1143-1154. [PMID: 32232658 DOI: 10.1007/s00421-020-04353-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/18/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE This study investigated whether regular precooling would help to maintain day-to-day training intensity and improve 20-km cycling time trial (TT) performed in the heat. Twenty males cycled for 10 day × 60 min at perceived exertion equivalent to 15 in the heat (35 °C, 50% relative humidity), preceded by no cooling (CON, n = 10) or 30-min water immersion at 22 °C (PRECOOL, n = 10). METHODS 19 participants (n = 9 and 10 for CON and PRECOOL, respectively) completed heat stress tests (25-min at 60% [Formula: see text] and 20-km TT) before and after heat acclimation. RESULTS Changes in mean power output (∆MPO, P = 0.024) and heart rate (∆HR, P = 0.029) during heat acclimation were lower for CON (∆MPO - 2.6 ± 8.1%, ∆HR - 7 ± 7 bpm), compared with PRECOOL (∆MPO + 2.9 ± 6.6%, ∆HR - 1 ± 8 bpm). HR during constant-paced cycling was decreased from the pre-acclimation test in both groups (P < 0.001). Only PRECOOL demonstrated lower rectal temperature (Tre) during constant-paced cycling (P = 0.002) and lower Tre threshold for sweating (P = 0.042). However, skin perfusion and total sweat output did not change in either CON or PRECOOL (all P > 0.05). MPO (P = 0.016) and finish time (P = 0.013) for the 20-km TT were improved in PRECOOL but did not change in CON (P = 0.052 for MPO, P = 0.140 for finish time). CONCLUSION Precooling maintains day-to-day training intensity and does not appear to attenuate adaptation to training in the heat.
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Affiliation(s)
- Hui C Choo
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Dr, Joondalup, WA, 6027, Australia. .,Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, Singapore, 117593, Singapore.
| | - Jeremiah J Peiffer
- Discipline of Exercise Science, College of Science, Health, Engineering and Education, Murdoch University, 90 South St, Murdoch, WA, 6150, Australia
| | - Joel W J Pang
- Sport Science and Medicine Centre, Singapore Sport Institute, 3 Stadium Drive, Singapore, 397630, Singapore
| | - Frankie H Y Tan
- Sport Science and Medicine Centre, Singapore Sport Institute, 3 Stadium Drive, Singapore, 397630, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, Singapore, 117593, Singapore
| | - Abdul Rashid Aziz
- Sport Science and Medicine Centre, Singapore Sport Institute, 3 Stadium Drive, Singapore, 397630, Singapore
| | - Mohammed Ihsan
- Research and Scientific Support, ASPETAR Orthopaedic and Sports Medicine Hospital, P.O. Box 29222, Doha, Qatar
| | - Jason K W Lee
- Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, Singapore, 117593, Singapore
| | - Chris R Abbiss
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Dr, Joondalup, WA, 6027, Australia
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15
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Benjamin CL, Sekiguchi Y, Fry LA, Casa DJ. Performance Changes Following Heat Acclimation and the Factors That Influence These Changes: Meta-Analysis and Meta-Regression. Front Physiol 2019; 10:1448. [PMID: 31827444 PMCID: PMC6890862 DOI: 10.3389/fphys.2019.01448] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/08/2019] [Indexed: 11/17/2022] Open
Abstract
Heat acclimation (HA) is the process of intentional and consistent exercise in the heat that results in positive physiological adaptations, which can improve exercise performance both in the heat and thermoneutral conditions. Previous research has indicated the many performance benefits of HA, however, a meta-analysis examining the magnitude of different types of performance improvement is absent. Additionally, there are several methodological discrepancies in the literature that could lead to increased variability in performance improvement following HA and no previous study has examined the impact of moderators on performance improvement following HA. Therefore, the aim of this study was two-fold; (1) to perform a meta-analysis to examine the magnitude of changes in performance following HA in maximal oxygen consumption (VO2max), time to exhaustion, time trial, mean power, and peak power tests; (2) to determine the impact of moderators on results of these performance tests. Thirty-five studies met the inclusion/exclusion criteria with 23 studies that assessed VO2max (n = 204), 24 studies that assessed time to exhaustion (n = 232), 10 studies that performed time trials (n = 101), 7 studies that assessed mean power (n = 67), and 10 papers that assessed peak power (n = 88). Data are reported as Hedge's g effect size (ES), and 95% confidence intervals (95% CI). Statistical significance was set to p < 0.05, a priori. The magnitude of change following HA was analyzed, with time to exhaustion demonstrating the largest performance enhancement (ES [95% CI], 0.86 [0.71, 1.01]), followed by time trial (0.49 [0.26, 0.71]), mean power (0.37 [0.05, 0.68]), VO2max (0.30 [0.07, 0.53]), and peak power (0.29 [0.09, 0.48]) (p < 0.05). When all of the covariates were analyzed as individual models, induction method, fitness level, heat index in time to exhaustion (coefficient [95% CI]; induction method, -0.69 [-1.01, -0.37], p < 0.001; fitness level, 0.04 [0.02, 0.06], p < 0.001; heat index, 0.04 [0.02, 0.07], p < 0.0001) and induction length in mean power (coefficient [95% CI]; induction length 0.15 [0.05, 0.25], p = 0.002) significantly impacted the magnitude of change. Sport scientists and researchers can use the findings from this meta-analysis to customize HA induction. For time to exhaustion improvements, HA implementation should focus on induction method and baseline fitness, while the training and recovery balance could lead to optimal time trial performance.
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Affiliation(s)
- Courteney Leigh Benjamin
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
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16
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Gibson OR, James CA, Mee JA, Willmott AG, Turner G, Hayes M, Maxwell NS. Heat alleviation strategies for athletic performance: A review and practitioner guidelines. Temperature (Austin) 2019; 7:3-36. [PMID: 32166103 PMCID: PMC7053966 DOI: 10.1080/23328940.2019.1666624] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/06/2019] [Accepted: 09/08/2019] [Indexed: 12/19/2022] Open
Abstract
International competition inevitably presents logistical challenges for athletes. Events such as the Tokyo 2020 Olympic Games require further consideration given historical climate data suggest athletes will experience significant heat stress. Given the expected climate, athletes face major challenges to health and performance. With this in mind, heat alleviation strategies should be a fundamental consideration. This review provides a focused perspective of the relevant literature describing how practitioners can structure male and female athlete preparations for performance in hot, humid conditions. Whilst scientific literature commonly describes experimental work, with a primary focus on maximizing magnitudes of adaptive responses, this may sacrifice ecological validity, particularly for athletes whom must balance logistical considerations aligned with integrating environmental preparation around training, tapering and travel plans. Additionally, opportunities for sophisticated interventions may not be possible in the constrained environment of the athlete village or event arenas. This review therefore takes knowledge gained from robust experimental work, interprets it and provides direction on how practitioners/coaches can optimize their athletes' heat alleviation strategies. This review identifies two distinct heat alleviation themes that should be considered to form an individualized strategy for the athlete to enhance thermoregulatory/performance physiology. First, chronic heat alleviation techniques are outlined, these describe interventions such as heat acclimation, which are implemented pre, during and post-training to prepare for the increased heat stress. Second, acute heat alleviation techniques that are implemented immediately prior to, and sometimes during the event are discussed. Abbreviations: CWI: Cold water immersion; HA: Heat acclimation; HR: Heart rate; HSP: Heat shock protein; HWI: Hot water immersion; LTHA: Long-term heat acclimation; MTHA: Medium-term heat acclimation; ODHA: Once-daily heat acclimation; RH: Relative humidity; RPE: Rating of perceived exertion; STHA: Short-term heat acclimation; TCORE: Core temperature; TDHA: Twice-daily heat acclimation; TS: Thermal sensation; TSKIN: Skin temperature; V̇O2max: Maximal oxygen uptake; WGBT: Wet bulb globe temperature.
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Affiliation(s)
- Oliver R. Gibson
- Centre for Human Performance, Exercise and Rehabilitation (CHPER), Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, UK
| | - Carl A. James
- Institut Sukan Negara (National Sports Institute), Kuala Lumpur, Malaysia
| | - Jessica A. Mee
- School of Sport and Exercise Sciences, University of Worcester, Worcester, UK
| | - Ashley G.B. Willmott
- Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, Cambridge, UK
| | - Gareth Turner
- Bisham Abbey National High-Performance Centre, English Institute of Sport, EIS Performance Centre, Marlow, UK
| | - Mark Hayes
- Environmental Extremes Laboratory, School of Sport and Service Management, University of Brighton, Eastbourne, UK
| | - Neil S. Maxwell
- Environmental Extremes Laboratory, School of Sport and Service Management, University of Brighton, Eastbourne, UK
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17
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Impairment of Cycling Capacity in the Heat in Well-Trained Endurance Athletes After High-Intensity Short-Term Heat Acclimation. Int J Sports Physiol Perform 2019; 14:1058-1065. [PMID: 30702375 DOI: 10.1123/ijspp.2018-0537] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/19/2018] [Accepted: 01/03/2019] [Indexed: 11/18/2022]
Abstract
PURPOSE To investigate the effects of short-term, high-intensity interval-training (HIIT) heat acclimation (HA). METHODS Male cyclists/triathletes were assigned into either an HA (n = 13) or a comparison (COMP, n = 10) group. HA completed 3 cycling heat stress tests (HSTs) to exhaustion (60% Wmax; HST1, pre-HA; HST2, post-HA; HST3, 7 d post-HA). HA consisted of 30-min bouts of HIIT cycling (6 min at 50% Wmax, then 12 × 1-min 100%-Wmax bouts with 1-min rests between bouts) on 5 consecutive days. COMP completed HST1 and HST2 only. HST and HA trials were conducted in 35°C/50% relative humidity. Cycling capacity and physiological and perceptual data were recorded. RESULTS Cycling capacity was impaired after HIIT HA (77.2 [34.2] min vs 56.2 [24.4] min, P = .03) and did not return to baseline after 7 d of no HA (59.2 [37.4] min). Capacity in HST1 and HST2 was similar in COMP (43.5 [8.3] min vs 46.8 [15.7] min, P = .54). HIIT HA lowered resting rectal (37.0°C [0.3°C] vs 36.8°C [0.2°C], P = .05) and body temperature (36.0°C [0.3°C] vs 35.8°C [0.3°C], P = .03) in HST2 compared with HST1 and lowered mean skin temperature (35.4°C [0.5°C] vs 35.1°C [0.3°C], P = .02) and perceived strain on day 5 compared with day 1 of HA. All other data were unaffected. CONCLUSIONS Cycling capacity was impaired in the heat after 5 d of consecutive HIIT HA despite some heat adaptation. Based on data, this approach is not recommended for athletes preparing to compete in the heat; however, it is possible that it may be beneficial if a state of overreaching is avoided.
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18
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Griggs KE, Stephenson BT, Price MJ, Goosey-Tolfrey VL. Heat-related issues and practical applications for Paralympic athletes at Tokyo 2020. Temperature (Austin) 2019; 7:37-57. [PMID: 32166104 PMCID: PMC7053936 DOI: 10.1080/23328940.2019.1617030] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 02/07/2023] Open
Abstract
International sporting competitions, including the Paralympic Games, are increasingly being held in hot and/or humid environmental conditions. Thus, a greater emphasis is being placed on preparing athletes for the potentially challenging environmental conditions of the host cities, such as the upcoming Games in Tokyo in 2020. However, evidence-based practices are limited for the impairment groups that are eligible to compete in Paralympic sport. This review aims to provide an overview of heat-related issues for Paralympic athletes alongside current recommendations to reduce thermal strain and technological advancements in the lead up to the Tokyo 2020 Paralympic Games. When competing in challenging environmental conditions, a number of factors may contribute to an athlete's predisposition to heightened thermal strain. These include the characteristics of the sport itself (type, intensity, duration, modality, and environmental conditions), the complexity and severity of the impairment and classification of the athlete. For heat vulnerable Paralympic athletes, strategies such as the implementation of cooling methods and heat acclimation can be used to combat the increase in heat strain. At an organizational level, regulations and specific heat policies should be considered for several Paralympic sports. Both the utilization of individual strategies and specific heat health policies should be employed to ensure that Paralympics athletes' health and sporting performance are not negatively affected during the competition in the heat at the Tokyo 2020 Paralympic Games.
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Affiliation(s)
- Katy E. Griggs
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Ben T. Stephenson
- Loughborough Performance Centre, English Institute of Sport, Loughborough University, Loughborough, UK
- Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Michael J. Price
- School of Life Sciences, Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, UK
| | - Victoria L. Goosey-Tolfrey
- Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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19
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Kirby NV, Lucas SJE, Lucas RAI. Nine-, but Not Four-Days Heat Acclimation Improves Self-Paced Endurance Performance in Females. Front Physiol 2019; 10:539. [PMID: 31156449 PMCID: PMC6532023 DOI: 10.3389/fphys.2019.00539] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/16/2019] [Indexed: 11/13/2022] Open
Abstract
Although emerging as a cost and time efficient way to prepare for competition in the heat, recent evidence indicates that "short-term" heat acclimation (<7 days) may not be sufficient for females to adapt to repeated heat stress. Furthermore, self-paced performance following either short-term, or longer (>7 days) heat acclimation has not been examined in a female cohort. Therefore, the aim of this study was to investigate self-paced endurance performance in hot conditions following 4- and 9-days of a high-intensity isothermic heat acclimation protocol in a female cohort. Eight female endurance athletes (mean ± SD, age 27 ± 5 years, mass 61 ± 5 kg, VO2peak 47 ± 6 ml⋅kg⋅min-1) performed 15-min self-paced cycling time trials in hot conditions (35°C, 30%RH) before (HTT1), and after 4-days (HTT2), and 9-days (HTT3) isothermic heat acclimation (HA, with power output manipulated to increase and maintain rectal temperature (T rec) at ∼38.5°C for 90-min cycling in 40°C, 30%RH) with permissive dehydration. There were no significant changes in distance cycled (p = 0.47), mean power output (p = 0.55) or cycling speed (p = 0.44) following 4-days HA (i.e., from HTT1 to HTT2). Distance cycled (+3.2%, p = 0.01; +1.8%, p = 0.04), mean power output (+8.1%, p = 0.01; +4.8%, p = 0.05) and cycling speed (+3.0%, p = 0.01; +1.6%, p = 0.05) were significantly greater in HTT3 than in HTT1 and HTT2, respectively. There was an increase in the number of active sweat glands per cm2 in HTT3 as compared to HTT1 (+32%; p = 0.02) and HTT2 (+22%; p < 0.01), whereas thermal sensation immediately before HTT3 decreased ("Slightly Warm," p = 0.03) compared to ratings taken before HTT1 ("Warm") in 35°C, 30%RH. Four-days HA was insufficient to improve performance in the heat in females as observed following 9-days HA.
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Affiliation(s)
- Nathalie V. Kirby
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
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20
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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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21
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Pryor JL, Johnson EC, Roberts WO, Pryor RR. Application of evidence-based recommendations for heat acclimation: Individual and team sport perspectives. Temperature (Austin) 2018; 6:37-49. [PMID: 30906810 PMCID: PMC6422510 DOI: 10.1080/23328940.2018.1516537] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 01/18/2023] Open
Abstract
Heat acclimation or acclimatization (HA) occurs with repeated exposure to heat inducing adaptations that enhance thermoregulatory mechanisms and heat tolerance leading to improved exercise performance in warm-to-hot conditions. HA is an essential heat safety and performance enhancement strategy in preparation for competitions in warm-to-hot conditions for both individual and team sports. Yet, some data indicate HA is an underutilized pre-competition intervention in athletes despite the well-known benefits; possibly due to a lack of practical information provided to athletes and coaches. Therefore, the aim of this review is to provide actionable evidence-based implementation strategies and protocols to induce and sustain HA. We propose the following suggestions to circumvent potential implementation barriers: 1) incorporate multiple induction methods during the initial acclimation period, 2) complete HA 1-3 weeks before competition in the heat to avoid training and logistical conflicts during the taper period, and 3) minimize adaptation decay through intermittent exercise-heat exposure or re-acclimating immediately prior to competition with 2-4 consecutive days of exercise-heat training. Use of these strategies may be desirable or necessary to optimize HA induction and retention around existing training or logistical requirements.
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Affiliation(s)
- J. Luke Pryor
- Department of Kinesiology, California State University, Fresno, CA, USA
| | - Evan C. Johnson
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, USA
| | - William O. Roberts
- Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - Riana R. Pryor
- Department of Kinesiology, California State University, Fresno, CA, USA
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22
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Optimizing Heat Acclimation for Endurance Athletes: High- Versus Low-Intensity Training. Int J Sports Physiol Perform 2018; 13:816-823. [DOI: 10.1123/ijspp.2017-0007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose: To determine the effect of high- versus low-intensity training in the heat and ensuing taper period in the heat on endurance performance. Methods: In total, 19 well-trained triathletes undertook 5 days of normal training and a 1-wk taper including either low- (heat acclimation [HA-L], n = 10) or high-intensity (HA-H, n = 9) training sessions in the heat (30°C, 50% relative humidity). A control group (n = 10) reproduced their usual training in thermoneutral conditions. Indoor 20-km cycling time trials (35°C, 50% relative humidity) were performed before (Pre) and after the main heat exposure (Mid) and after the taper (Post). Results: Power output remained stable in the control group from Pre to Mid (effect size: −0.10 [0.26]) and increased from Mid to Post (0.18 [0.22]). The HA-L group demonstrated a progressive increase in performance from Pre to Mid (0.62 [0.33]) and from Mid to Post (0.53 [0.30]), alongside typical physiological signs of HA (reduced core temperature and heart rate and increased body-mass loss). While the HA-H group presented similar adaptations, increased perceived fatigue and decreased performance at Mid (−0.35 [0.26]) were evidenced and reversed at Post (0.50 [0.20]). No difference in power output was reported at Post between the HA-H and control groups. Conclusion: HA-H can quickly induce functional overreaching in nonacclimatized endurance athletes. As it was associated with a weak subsequent performance supercompensation, coaches and athletes should pay particular attention to training monitoring during a final preparation in the heat and reduce training intensity when early signs of functional overreaching are identified.
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23
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Casadio JR, Kilding AE, Cotter JD, Laursen PB. From Lab to Real World: Heat Acclimation Considerations for Elite Athletes. Sports Med 2018; 47:1467-1476. [PMID: 28035584 DOI: 10.1007/s40279-016-0668-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
As major sporting events are often held in hot environments, increased interest in ways of optimally heat acclimating athletes to maximise performance has emerged. Heat acclimation involves repeated exercise sessions in hot conditions that induce physiological and thermoregulatory adaptations that attenuate heat-induced performance impairments. Current evidence-based guidelines for heat acclimation are clear, but the application of these recommendations is not always aligned with the time commitments and training priorities of elite athletes. Alternative forms of heat acclimation investigated include hot water immersion and sauna bathing, yet uncertainty remains around the efficacy of these methods for reducing heat-induced performance impairments, as well as how this form of heat stress may add to an athlete's overall training load. An understanding of how to optimally prescribe and periodise heat acclimation based on the performance determinants of a given event is limited, as is knowledge of how heat acclimation may affect the quality of concurrent training sessions. Finally, differences in individual athlete responses to heat acclimation need to be considered. This article addresses alternative methods of heat acclimation and heat exposure, explores gaps in literature around understanding the real world application of heat acclimation for athletes, and highlights specific athlete considerations for practitioners.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand.
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand
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24
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Skein M, Wingfield G, Gale R, Washington TL, Minett GM. Sleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recovery. J Therm Biol 2018; 74:63-70. [DOI: 10.1016/j.jtherbio.2018.03.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
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25
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Stevens CJ, Plews DJ, Laursen PB, Kittel AB, Taylor L. Acute physiological and perceptual responses to wearing additional clothing while cycling outdoors in a temperate environment:A practical method to increase the heat load. Temperature (Austin) 2017; 4:414-419. [PMID: 29435480 DOI: 10.1080/23328940.2017.1365108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/30/2017] [Accepted: 08/03/2017] [Indexed: 10/18/2022] Open
Abstract
This investigation assessed the acute physiological and perceptual responses to wearing additional clothing during outdoor cycling to determine if this strategy could increase the heat load while training in temperate environments. Seven male cyclists (age: 32 ± 13 y, height: 179 ± 10 cm, body mass: 74 ± 10 kg, body fat percentage: 10.3 ± 1.0%) completed 2 randomized outdoor (∼17°C and ∼82% RH), 80 min cycling sessions at moderate-hard intensities (CR10 RPE = 3-5). They wore spandex shorts and a short sleeve top (CON) or additional clothing including full-length spandex pants and a 'winter' cycling jacket and gloves (AC). Core temperature, heart rate, sweat rate, thermal sensation and thermal comfort were measured across the trials. Moderate increases were observed in AC vs. CON for the change in mean core temperature (0.4 ± 0.3°C, effect size, ES = 1.16 ± 0.55), change in maximum core temperature (0.5 ± 0.3°C, ES = 1.07 ± 0.48) and sweat rate (0.24 ± 0.16 L . h-1, ES = 1.04 ± 0.59). A small increase in mean heart rate (3 ± 3 bpm, ES = 0.32 ± 0.28) was observed as well as a 'very likely' (percentage difference = 22.4 ± 7.1) and 'most likely' (percentage difference = 42.9 ± 11.9) increase in thermal sensation and thermal comfort, respectively, in AC vs. CON. Dressing in additional clothing while cycling outdoors in a temperate environment increased physiological strain and sensations of warmth and discomfort. Training in additional clothing during outdoor cycling represents a practical alternative to increasing the heat load of a training session.
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Affiliation(s)
- Christopher J Stevens
- School of Health and Human Sciences, Southern Cross University, Coffs Harbour, Australia
| | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.,Kitman Labs, Dublin, Ireland
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Aden B Kittel
- College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Lee Taylor
- ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
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26
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Guy JH, Pyne DB, Deakin GB, Miller CM, Edwards AM. Acclimation Training Improves Endurance Cycling Performance in the Heat without Inducing Endotoxemia. Front Physiol 2016; 7:318. [PMID: 27524970 PMCID: PMC4965461 DOI: 10.3389/fphys.2016.00318] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/13/2016] [Indexed: 12/02/2022] Open
Abstract
Purpose: While the intention of endurance athletes undertaking short term heat training protocols is to rapidly gain meaningful physical adaption prior to competition in the heat, it is currently unclear whether or not this process also presents an overt, acute challenge to the immune system. The aim of this study was therefore to examine the effects of heat training on both endurance performance and biomarkers associated with inflammatory and immune system responses. Methods: Moderately-actively males (n = 24) were allocated randomly to either HOT (n = 8, 35°C, and 70% RH; NEUTRAL (n = 8, 20°C, and 45% RH); or a non-exercising control group, (CON, n = 8). Over the 18 day study HOT and NEUTRAL performed seven training sessions (40 min cycling at 55 of VO2 max) and all participants completed three heat stress tests (HST) at 35°C and 70% RH. The HST protocol comprised three × sub-maximal intervals followed by a 5 km time trial on a cycle ergometer. Serum samples were collected before and after each HST and analyzed for interleukin-6, immunoglobulin M and lipopolysaccharide. Results: Both HOT and NEUTRAL groups experienced substantial improvement to 5 km time trial performance (HOT −33 ± 20 s, p = 0.02, NEUTRAL −39 ± 18 s, p = 0.01) but only HOT were faster (−45 ± 25 s, and −12 s ± 7 s, p = 0.01) in HST3 compared to baseline and HST2. Interleukin-6 was elevated after exercise for all groups however there were no significant changes for immunoglobulin M or lipopolysaccharide. Conclusions: Short-term heat training enhances 5 km cycling time trial performance in moderately-fit subjects by ~6%, similar in magnitude to exercise training in neutral conditions.Three top-up training sessions yielded a further 3% improvement in performance for the HOT group. Furthermore, the heat training did not pose a substantial challenge to the immune system.
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Affiliation(s)
- Joshua H Guy
- Department of Sport and Exercise Science, James Cook UniversityCairns, QLD, Australia; Faculty of Sport and Health Sciences, University of St Mark & St JohnPlymouth, UK
| | - David B Pyne
- Department of Sport and Exercise Science, James Cook UniversityCairns, QLD, Australia; Department of Physiology, Australian Institute of SportCanberra, ACT, Australia
| | - Glen B Deakin
- Department of Sport and Exercise Science, James Cook University Cairns, QLD, Australia
| | - Catherine M Miller
- Biomedical Sciences, College of Public Health, Medical and Vet Sciences, James Cook University Cairns, QLD, Australia
| | - Andrew M Edwards
- Department of Sport and Exercise Science, James Cook UniversityCairns, QLD, Australia; Faculty of Sport and Health Sciences, University of St Mark & St JohnPlymouth, UK
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