HYPEROXIA DURING RECOVERY FROM CONSECUTIVE ANAEROBIC EXERCISES IN THESICKLE-CELL TRAIT

The sickle cell trait (HbAS) does not affect anaerobic exercise perfor mance. However, lower blood lactate concentrations ([La-]) are consist ently found during repeated anaerobic exercise in HbAS, and could be r elated to type of recovery. To study this, on three different occasion s 17HbAS and 17 matched control athletes (HbAA) underwent a series of three maximal cycle exercise tests of approximately 2-min duration, se parated by 10-min recovery periods of rest, breathing either room air (P) or 100% oxygen (H), or of light pedaling (A). In all tests, work p erformed, heart rate, blood hematocrit, and [La-] were measured. Despi te similar evolution of performance in each series of three anaerobic exercises, significantly lower [La-] were consistently found in HbAS i n P and A, compared to HbAA (P < 0.0001). However, in H, similar [La-] was found in HbAS and HbAA. Higher mean heart rates were consistently measured in HbAS at exhaustion, and during the first 4 min of recover y, these differences being unrelated to type of recovery. We conclude that type of recovery does not influence subsequent performance in HbA S or HbAA. We speculate that improved regional oxygen availability in exercising muscle is associated with marked modification of lactate ki netics in highly trained HbAS, but not in similarly fit HbAA athletes.