Related Trends in Locomotor and Respiratory Muscle Oxygenation during Exercise

Abstract

In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.