Ischemic preconditioning accelerates muscle deoxygenation dynamics and enhances exercise endurance during the work‐to‐work test

Physiological Reports

Kohei Kido¹  Tadashi Suga¹  Daichi Tanaka¹  Toyoyuki Honjo¹  Toshiyuki Homma¹  Satoshi Fujita¹  Takafumi Hamaoka¹ 

[1] Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan

关键词: Exercise;    mitochondria;    near‐infrared spectroscopy;    nitric oxide;    skeletal muscle;   

DOI  :  10.14814/phy2.12395

来源: Wiley

【 摘 要 】

Abstract

Ischemic preconditioning (IPC) improves maximal exercise performance. However, the potential mechanism(s) underlying the beneficial effects of IPC remain unknown. The dynamics of pulmonary oxygen uptake (VO₂) and muscle deoxygenation during exercise is frequently used for assessing O₂ supply and extraction. Thus, this study examined the effects of IPC on systemic and local O₂ dynamics during the incremental step transitions from low- to moderate- and from moderate- to severe-intensity exercise. Fifteen healthy, male subjects were instructed to perform the work-to-work cycling exercise test, which was preceded by the control (no occlusion) or IPC (3 × 5 min, bilateral leg occlusion at >300 mmHg) treatments. The work-to-work test was performed by gradually increasing the exercise intensity as follows: low intensity at 30 W for 3 min, moderate intensity at 90% of the gas exchange threshold (GET) for 4 min, and severe intensity at 70% of the difference between the GET and VO₂ peak until exhaustion. During the exercise test, the breath-by-breath pulmonary VO₂ and near-infrared spectroscopy-derived muscle deoxygenation were continuously recorded. Exercise endurance during severe-intensity exercise was significantly enhanced by IPC. There were no significant differences in pulmonary VO₂ dynamics between treatments. In contrast, muscle deoxygenation dynamics in the step transition from low- to moderate-intensity was significantly faster in IPC than in CON (27.2 ± 2.9 vs. 19.8 ± 0.9 sec, P < 0.05). The present findings showed that IPC accelerated muscle deoxygenation dynamics in moderate-intensity exercise and enhanced severe-intensity exercise endurance during work-to-work test. The IPC-induced effects may result from mitochondrial activation in skeletal muscle, as indicated by the accelerated O₂ extraction.

【 授权许可】

CC BY   
© 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

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