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Home / Equine Research Bank / Physiol Rep / Heat acclimation improves exercise performance in hot condit...
Physiological reports2024; 12(10); e16083; doi: 10.14814/phy2.16083

Heat acclimation improves exercise performance in hot conditions and increases heat shock protein 70 and 90 of skeletal muscles in Thoroughbred horses.

Abstract: This study aimed to determine whether heat acclimation could induce adaptations in exercise performance, thermoregulation, and the expression of proteins associated with heat stress in the skeletal muscles of Thoroughbreds. Thirteen trained Thoroughbreds performed 3 weeks of training protocols, consisting of cantering at 90% maximal oxygen consumption (VO2max) for 2 min 2 days/week and cantering at 7 m/s for 3 min 1 day/week, followed by a 20-min walk in either a control group (CON; Wet Bulb Globe Temperature [WBGT] 12-13°C; n = 6) or a heat acclimation group (HA; WBGT 29-30°C; n = 7). Before and after heat acclimation, standardized exercise tests (SET) were conducted, cantering at 7 m/s for 90 s and at 115% VO2max until fatigue in hot conditions. Increases in run time (p = 0.0301), peak cardiac output (p = 0.0248), and peak stroke volume (p = 0.0113) were greater in HA than in CON. Pulmonary artery temperature at 7 m/s was lower in HA than in CON (p = 0.0332). The expression of heat shock protein 70 (p = 0.0201) and 90 (p = 0.0167) increased in HA, but not in CON. These results suggest that heat acclimation elicits improvements in exercise performance and thermoregulation under hot conditions, with a protective adaptation to heat stress in equine skeletal muscles.
© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.
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Publication Date: 2024-05-25 PubMed ID: 38789393PubMed Central: PMC11126422DOI: 10.14814/phy2.16083Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research paper explores how heat acclimation can improve the performance of Thoroughbred horses by increasing heat shock proteins in their muscles and improving their thermoregulation.

Introduction and Objectives

  • The main aim of the study was to find out if acclimatisation to hot conditions could improve exercise performance, help with regulation of body temperature and increase the expression of proteins linked with heat stress in the muscles of Thoroughbred horses.

Methodology

  • Thirteen trained Thoroughbred horses were put through a three-week course of training exercises under either control (CON; normal temperature conditions) or heat acclimation (HA; high temperature conditions).
  • The training protocol consisted of running at 90% of their maximum oxygen consumption (VO) for two minutes, two days a week, and running for three minutes at a speed of 7 m/s one day a week, followed by a 20-minute walk.
  • The horses’ exercise performance was tested at 7 m/s for 90 seconds and at 115% VO to the point of exhaustion in hot conditions, before and after the heat acclimation process.

Results

  • Horses who trained in the heat acclimation environment showed greater improvements in running time, peak cardiac output, and peak stroke volume compared to the horses in the control group.
  • The internal body temperature (pulmonary artery temperature) at speeds of 7m/s was lesser in heat-acclimated horses than in the control group, indicating better thermoregulation.
  • The expression of heat shock proteins 70 and 90, which protect against heat stress, increased in the HA group horses but not in the CON group horses.

Conclusion

  • The results of the study indicate that heat acclimation has positive effects on training performance and the capability of Thoroughbred horses to manage bodily temperatures in hot conditions. Moreover, there is an increase in the production of proteins that play a role in heat stress protection in their muscles.

Cite This Article

APA
Ebisuda Y, Mukai K, Takahashi Y, Yoshida T, Matsuhashi T, Kawano A, Miyata H, Kuwahara M, Ohmura H. (2024). Heat acclimation improves exercise performance in hot conditions and increases heat shock protein 70 and 90 of skeletal muscles in Thoroughbred horses. Physiol Rep, 12(10), e16083. https://doi.org/10.14814/phy2.16083

Publication

Physiological reports
ISSN: 2051-817X
NlmUniqueID: 101607800
Country: United States
Language: English
Volume: 12
Issue: 10
Pages: e16083

Researcher Affiliations

Ebisuda, Yusaku
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan.
Mukai, Kazutaka
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan.
Takahashi, Yuji
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan.
Yoshida, Toshinobu
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan.
Matsuhashi, Tsubasa
  • Department of Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan.
Kawano, Aoto
  • Department of Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan.
Miyata, Hirofumi
  • Department of Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan.
Kuwahara, Masayoshi
  • Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Ohmura, Hajime
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan.

MeSH Terms

  • Animals
  • Horses / physiology
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiology
  • Physical Conditioning, Animal / methods
  • Physical Conditioning, Animal / physiology
  • HSP70 Heat-Shock Proteins / metabolism
  • Acclimatization / physiology
  • Male
  • Hot Temperature
  • Body Temperature Regulation / physiology
  • Oxygen Consumption / physiology
  • Heat-Shock Response / physiology

Grant Funding

  • N/A / Japan Racing Association (JRA)

Conflict of Interest Statement

This study was funded by the Japan Racing Association. YE, KM, YT, TY, and HO are employees of the Japan Racing Association.

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