open access

https://hdl.handle.net/2115/43990

Effect of prolonged exercise on pulmonary gas exchange during decremental-load exercise

英語

ventilatory equivalent for CO2

1997

日本運動生理学会

Advances in Exercise and Sports Physiology

3(1)

23-28

The effects of prolonged exercise on pulmonary gas exchange during decremental-load exercise were investigated. Eight healthy male subjects participated in two experiments. In the first experiment, maximal incremental-load exercise (ILE) was used to determine the maximal work rate and peak oxygen uptake (peak V02). In the second experiment, subjects exercised for one hour following a first decremental-load exercise (DLE1) starting from the maximal work rate determined by the first experiment and then again following a second decremental-load exercise (DLE2). V02, measured every ten minutes during the prolonged exercise, was around 50% of the peak value at 10min, increasing to around 60% at 60min. Total O2, the sum of O2 uptake (V02) from the start to the end of the exercise, was significantly lower during DLE2 than DLE1. Total CO2, the sum of CO2 output (VC02) was significantly lower during DLE2 than DLE1. Although VC02 tended to be lower during DLE2 than DLE1 at almost all work rates, this difference was only significant at high work rates. The results for V02 and VC02 suggested a smaller increase in lactate during DLE2 than DLE1. The ventilatory equivalent for CO2 at a higher work rate was significantly higher during DLE2 than DLE1. This increase was thought to be related to muscle glycogen depletion induced by DLE1 and prolonged exercise. In conclusion, after prolonged exercise, pulmonary gas exchange kinetics during decremental-load exercise changed as follows; total O2 uptake and CO2 output decreased, the ventilatory equivalent for CO2 at a higher work rate increased. The mechanism by which excess CO2 is removed without increasing pulmonary ventilation remains to be elucidated.

学術雑誌論文

Version of Record

1340-3141