Relationship between tissue oxygen index in skeletal muscle and oxygen uptake at pulmonary level

英語

Oxygen tissue index

北海道大学大学院教育学研究院

北海道大学大学院教育学研究院紀要

　We examined whether the relationship between muscle oxygen consumption and lung oxygen uptake is established by the intervention of cardiac pumping. Oxygen intake (V・o2) and heart rate (HR) were determined breath-by-breath. The values were converted to 1-second values by a three-dimensional spine function. Tissue oxygen index (TOI) was determined per second from the vastus lateralis by using near-infrared spectroscopy. Exercise was performed for 10 seconds with an intensity of 70% of peak V・o2. A rest period of 10 minutes after exercise was set before the exercise and a recovery period of 20 minutes was set after the exercise. All 1-second values during the test were processed with a low pass filter (<0.05 Hz). Cross-correlation of the processed values was obtained. V・o2 rose during exercise and increased again during recovery. HR rose during exercise and declined during recovery. TOI decreased after exercise and increased during recovery. The maximum value of the cross-correlation between HR and V・o2 was 0.712 ± 0.112. The minimum cross-correlation value between TOI and HR was -0.398 ± 0.225. Double of the time difference between the highest value and the lowest value of HR and V・o2 or TOI and HR is the wavelength. It was 170 seconds (2.8 minutes). The results suggested that variation in TOI or its related substances in skeletal muscle (oscillation and level of the oscillation axis) is partly related to variation in cardiac pumping and that variation in the cardiac pump considerable affects variation of lung oxygen intake.