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Home / Equine Research Bank / Physiol Rep / Moderate-intensity training in hypoxia improves exercise per...
Physiological reports2021; 9(23); e15145; doi: 10.14814/phy2.15145

Moderate-intensity training in hypoxia improves exercise performance and glycolytic capacity of skeletal muscle in horses.

Abstract: We investigated whether moderate-intensity training of horses in moderate hypoxia for 4 weeks elicits greater adaptations in exercise performance, aerobic capacity, and glycolytic/oxidative metabolism in skeletal muscle compared to normoxic training. In a randomized crossover study design, seven untrained Thoroughbred horses (5.9 ± 1.1 years, 508 ± 9 kg) completed 4 weeks (3 sessions/week) of two training protocols consisting of 3-min cantering at 70% of maximal oxygen consumption ( ) in hypoxia (HYP; F O  = 14.7%) and normoxia (NOR; F O  = 21.0%) with a 4-month washout period. Normoxic incremental exercise tests (IET) were conducted before and after training. Biopsy samples were obtained from the middle gluteal muscle before IET and monocarboxylate transporter (MCT) protein expression and glycolytic/mitochondrial enzyme activities were analyzed. Data were analyzed using mixed models (p < 0.05). Running speed was 7.9 ± 0.2 m/s in both groups and arterial oxygen saturation during training in NOR and HYP were 92.9 ± 0.9% and 75.7 ± 3.9%, respectively. Run time in HYP (+9.7%) and in both groups (NOR, +6.4%; HYP, +4.3%) at IET increased after 4 weeks of training. However, cardiac output, arterial-mixed venous O difference, and hemoglobin concentration at exhaustion were unchanged in both conditions. While MCT1 protein and citrate synthase activity did not increase in both conditions after training, MCT4 protein (+13%), and phosphofructokinase activity (+42%) increased only in HYP. In conclusion, 4 weeks of moderate-intensity hypoxic training improves exercise performance and glycolytic capacity of skeletal muscle in horses.
© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.
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Publication Date: 2021-12-11 PubMed ID: 34889527PubMed Central: PMC8661515DOI: 10.14814/phy2.15145Google Scholar: Lookup
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  • Non-U.S. Gov't

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.

The research article investigates the effects of training horses in hypoxic (low oxygen) conditions compared to normoxic (normal oxygen) conditions. The findings suggest horses trained under hypoxic conditions show improvements in exercise performance and muscle glycolytic capacity.

Objective of the Study

  • The main aim of the study was to determine whether training horses in moderate hypoxia for 4 weeks could cause greater improvements in their performance, aerobic capacity, and skeletal muscle glycolytic/oxidative metabolism, compared to training under normoxic conditions.

Methodology

  • The researchers used a randomized crossover study design involving seven untrained Thoroughbred horses.
  • Horses completed four-week training under two conditions – one in hypoxia (14.7% oxygen) and another in normoxia (21% oxygen), with a time of 3 months in between the two exercises.
  • The training consisted of cantering for 3 minutes at 70 percent of maximal oxygen consumption, three times a week.
  • Muscle biopsies were taken before and after the exercises, and tests for monocarboxylate transporter protein expression and glycolytic/mitochondrial enzyme activities were conducted.

Results

  • The run time of the horses in hypoxia increased by 9.7% and in both groups by about 6-7% after four weeks of training; however, there was no significant change in cardiac output or hemoglobin concentration.
  • Get an increase was observed in the phosphofructokinase activity by 42% and in MCT4 protein by 13% only in hypoxia, but no change was observed in MCT1 protein and citrate synthase activity in either condition.

Conclusion

  • The findings from the study suggest that four weeks of moderate-intensity hypoxic training can improve exercise performance and the glycolytic capacity of skeletal muscle in horses.
  • This suggests that hypoxic training could potentially be beneficial for equine athletes and horses required to perform physically demanding tasks.

Cite This Article

APA
Mukai K, Kitaoka Y, Takahashi Y, Takahashi T, Takahashi K, Ohmura H. (2021). Moderate-intensity training in hypoxia improves exercise performance and glycolytic capacity of skeletal muscle in horses. Physiol Rep, 9(23), e15145. https://doi.org/10.14814/phy2.15145

Publication

Physiological reports
ISSN: 2051-817X
NlmUniqueID: 101607800
Country: United States
Language: English
Volume: 9
Issue: 23
Pages: e15145
PII: e15145

Researcher Affiliations

Mukai, Kazutaka
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
Kitaoka, Yu
  • Department of Human Sciences, Kanagawa University, Yokohama, Kanagawa, Japan.
Takahashi, Yuji
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
Takahashi, Toshiyuki
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
Takahashi, Kenya
  • Department of Sports Sciences, University of Tokyo, Tokyo, Japan.
Ohmura, Hajime
  • Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.

MeSH Terms

  • Animals
  • Exercise Tolerance / physiology
  • Female
  • Glycolysis / physiology
  • Horses / physiology
  • Hypoxia
  • Male
  • Muscle, Skeletal / physiology
  • Oxygen Consumption / physiology
  • Physical Conditioning, Animal / physiology

Conflict of Interest Statement

KM, HO, YT, and TT are employees of the Japan Racing Association.

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Citations

This article has been cited 6 times.
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