Abstract des Autors

To determine the effect of the duration of incremental exercise on the point at which arterial blood lactate concentration (HLa) increases above the resting value (anaerobic threshold: AT) and on the point at which HLa reaches a constant value of 4 mM (onset of blood lactate accummulation: OBLA), eight male students performed two different kinds of incremental exercise. The incremental bicycle exercise tests consisted of 25 W increase every minute (1-min test) and every 4 min (4-min test). At OBLA and AT, there were no significant differences in gas exchange parameters during the 1-min and 4-min tests except for the workload. When venous blood HLa was used instead of arterial HLa for a 4-min test, AT was not significantly different from that obtained by arterial HLa, but OBLA was significantly different. On the other hand, for the 1-min test, venous HLa values yielded significantly higher AT and OBLA compared with those obtained using arterial HLa. It was concluded that when arterial blood was used, there was no effect of duration of workload increase on the determination of the AT and OBLA expressed in VO2. On the other hand, when venous HLa was used instead of arterial blood, these points might be overestimated when a fast increase in workload, such as the 1-min test, is used.