Plasma volume responses to consecutive anaerobic exercise tests

This study examined the change in plasma volume (%ΔPV) in response to consecutive Wingate tests (30 sec Anaerobic Power test). Twelve active men (21 ± 1.6 yr, 81.3 ± 6.6 kg) performed two Wingate tests (W1 and W2, separated by 10 min) on three occasions (T1-T3, tests were two weeks apart). Exercise resistance was maintained at 75 g·kg^-1 body weight during testing. Blood samples were taken immediately before (Pre) and after (IF) W1 and W2. There were no significant differences in hematocrit, hemoglobin, mean power (MP) or peak power (PP) between T1-T3. There was a marked hemoconcentration in response to W1 (IF W1, -17.4 ± 2.6 %ΔPV), with a further, but not significantly greater, hemoconcentration following W2 (IF W2, -8.2 ± 1.1 %ΔPV). The %ΔPV, between PRE W1 and IP W2 was -20.1 ± 3.1%. These results suggest that an existing hemoconcentration (W1) may affect the magnitude of the %ΔPV response to subsequent supramaximal exercise (W2).