Four weeks of high-intensity training in moderate, but not mild hypoxia improves performance and running economy more than normoxic training in horses.

Publisher: published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society Country of Publication: United States NLM ID: 101607800 Publication Model: Print Cited Medium: Internet ISSN: 2051-817X (Electronic) Linking ISSN: 2051817X NLM ISO Abbreviation: Physiol Rep Subsets: MEDLINE

Original Publication: [Malden MA] : published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society, 2013-

Cardiorespiratory Fitness* ; Hypoxia* ; Physical Conditioning, Animal* ; Physical Endurance* ; Running*; Horses/*physiology; Animals ; Biomarkers/blood ; Cross-Over Studies ; Exercise Test/veterinary ; Exercise Tolerance ; Female ; Heart Rate ; Horses/blood ; Lactic Acid/blood ; Male ; Oxygen Consumption ; Time Factors

We investigated whether horses trained in moderate and mild hypoxia demonstrate greater improvement in performance and aerobic capacity compared to horses trained in normoxia and whether the acquired training effects are maintained after 2 weeks of post-hypoxic training in normoxia. Seven untrained Thoroughbred horses completed 4 weeks (3 sessions/week) of three training protocols, consisting of 2-min cantering at 95% maximal oxygen consumption V ˙ O 2 max under two hypoxic conditions (H16, F I O 2  = 16%; H18, F I O 2  = 18%) and in normoxia (N21, F I O 2  = 21%), followed by 2 weeks of post-hypoxic training in normoxia, using a randomized crossover study design with a 3-month washout period. Incremental treadmill tests (IET) were conducted at week 0, 4, and 6. The effects of time and groups were analyzed using mixed models. Run time at IET increased in H16 and H18 compared to N21, while speed at V ˙ O 2 max was increased significantly only in H16. V ˙ O 2 max in all groups and cardiac output at exhaustion in H16 and H18 increased after 4 weeks of training, but were not significantly different between the three groups. In all groups, run time, V ˙ O 2 max , V V ˙ O 2 max , Q ˙ max , and lactate threshold did not decrease after 2 weeks of post-hypoxic training in normoxia. These results suggest that 4 weeks of training in moderate (H16), but not mild (H18) hypoxia elicits greater improvements in performance and running economy than normoxic training and that these effects are maintained for 2 weeks of post-hypoxic training in normoxia.
(© 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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Keywords: horse; hypoxic training; performance; running economy

0 (Biomarkers)
33X04XA5AT (Lactic Acid)

Date Created: 20210221 Date Completed: 20211209 Latest Revision: 20221005

20250114

PMC7897453

10.14814/phy2.14760

33611843