%0 Journal Article
%T Effects of muscle cooling on kinetics of pulmonary oxygen uptake and muscle deoxygenation at the onset of exercise
%A Hideki Takagi
%A Hiroyuki Sakaue
%A Hitoshi Wakabayashi
%A Ke Li
%A Mizuki Osawa
%A Shunsaku Koga
%A Yasuo Sengoku
%J Archive of "Physiological Reports".
%D 2018
%R 10.14814/phy2.13910
%X This study investigated effects of skeletal muscle cooling on the metabolic response and kinetics of pulmonary oxygen uptake ( V¨B O2) and skeletal muscle deoxygenation during submaximal exercise. In the cooling condition (C), after immersion of the lower body into 12¡ãC 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 ¡À 1.7 and 2.4 ¡À 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¨B O2 kinetics (mean response time) was observed in C (45.6 ¡À 7.8 and 36.1 ¡À 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¨B O2 kinetics at the onset of exercise
%K Cold skeletal muscle
%K glycolytic metabolism
%K near©\infrared spectroscopy
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6209689/