Influence of cycle exercise on acetone in expired air and skin gas.

This study investigated the influence of cycle exercise on acetone concentration in expired air and skin gas. The subjects for this experiment were eight healthy males. Subjects performed a continuous graded exercise test on a cycle ergometer. The workloads were 360 (1.0 kg), 720 (2.0 kg), 990 (2.75 kg) kgm/min, and each stage was 5 min in duration. A pedaling frequency of 60 rpm was maintained. Acetone concentration was analyzed by gas chromatography. The acetone concentration in expired air and skin gas during exercise at 990 kgm/min intensity was significantly increased compared with the basal level. The skin-gas acetone concentration at 990 kgm/min significantly increased compared with the 360 kgm/min (P < 0.05). The acetone excretion of expired air at 720 kgm/min and 990 kgm/min significantly increased compared with the basal level (P < 0.05). Acetone concentration in expired air was 4-fold greater than skin gas at rest and 3-fold greater during exercise (P < 0.01). Skin gas acetone concentration significantly related with expired air (r = 0.752; P < 0.01). This study confirmed that the skin-gas acetone concentration reflected that of expired air.