Open AccessEffects of muscle cooling on kinetics of pulmonary oxygen uptake and muscle deoxygenation at the onset of exercise
Author(s) -
Wakabayashi Hitoshi,
Osawa Mizuki,
Koga Shunsaku,
Li Ke,
Sakaue Hiroyuki,
Sengoku Yasuo,
Takagi Hideki
Publication year - 2018
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13910
Subject(s) - deoxygenation , myoglobin , medicine , vastus lateralis muscle , skeletal muscle , oxygen , hemoglobin , chemistry , deoxygenated hemoglobin , cardiorespiratory fitness , endocrinology , kinetics , vo2 max , heart rate , oxygen saturation , biochemistry , blood pressure , physics , organic chemistry , quantum mechanics , catalysis
This study investigated effects of skeletal muscle cooling on the metabolic response and kinetics of pulmonary oxygen uptake ( V ˙ O 2 ) and skeletal muscle deoxygenation during submaximal exercise. In the cooling condition (C), after immersion of the lower body into 12°C water for 30 min, eight healthy males performed 30‐min cycling exercise at the lactate threshold while undergoing thigh cooling by a water‐circulating pad. In the normal condition (N) as control, they conducted the same exercise protocol without cooling. Blood lactate concentration was significantly higher in C than N at 10 min after onset of exercise (4.0 ± 1.7 and 2.4 ± 1.2 mmol/L in C and N, P < 0.05). The percent change in the tissue oxygen saturation of the vastus lateralis, measured by a near‐infrared spectroscopy, was significantly lower in C at 2, 8, 10, and 20 min after the exercise onset compared with N ( P < 0.05). The percent change in deoxy hemoglobin+myoglobin concentration (Deoxy[Hb+Mb]) showed a transient peak at the onset of exercise and significantly higher value in C at 10, 20, and 30 min after the exercise onset ( P < 0.05). Compared to N, slower V ˙ O 2 kinetics (mean response time) was observed in C (45.6 ± 7.8 and 36.1 ± 7.7 sec in C and N, P < 0.05). The mean response time in C relative to N was significantly correlated with the transient peak of Deoxy[Hb+Mb] in C ( r = 0.84, P < 0.05). These results suggest that lower oxygen delivery to the hypothermic skeletal muscle might induce greater glycolytic metabolism during exercise and slower V ˙ O 2 kinetics at the onset of exercise.