Blood Lactate Removal During Active Recovery Related to the Aerobic Threshold

Abstract

This study compared the variance in blood lactate (LA) removal (LAR) following intense exercise for 15 subjects during rest or active recovery (AR) at intensities expressed relative to V̇O₂max and the Aerobic Threshold (AerT). Two 3-min, 30 W incremental tests on the cycle ergometer were used to determine V̇O₂max (51.8 ± 4.6 ml·kg^-1·min^-1) and AerT (52.9 ± 4.7% V̇O₂max). AerT was determined from an initial continuous rise in LA above resting values and from the 1st “break” in V̇_E vs V̇O₂. Subjects performed six randomly ordered bouts of 10 min of exercise at 90% V̇O₂max, followed by 1 min of rest and either 20 min of further rest or AR at AerT-30% (A-30), -20% (A-20), -10% (A-10), ±10% (A), or +10% V̇O₂max (A+10). LA was determined after the 10 min of exercise and each 3 min of recovery. The calculation of individual half-times (t 1/2) for LAR revealed a significantly slower t 1/2 for rest compared to any AR and faster t 1/2 for A-20, A-10, and A compared to A+10. Regression analysis revealed no difference in r ² (0.74-0.77) for t 1/2 of LAR for all recovery conditions with intensity expressed as% V̇O₂max or AerT ±% V̇O₂max. With rest recovery data excluded, however, a greater proportion of the variance in LAR was explained with intensity expressed as AerT ±% V̇O₂max (r ² = 0.77) than as% V̇O₂max (r ² = 0.64). Peak LAR during AR was predicted to occur at AerT-10% V̇O₂max. It is concluded that AR slightly below AerT improves LAR compared to rest or AR above AerT. Expressing AR intensity as AerT ±% V̇O₂max decreases the interindividual variance.

Key words

high-intensity exercise - optimal recovery intensity - individual variability