Prior heavy exercise enhances performance during subsequent perimaximal exercise

Purpose: To test the hypothesis that prior heavy exercise increases the time to exhaustion during subsequent perimaximal exercise. Methods: Seven healthy males (mean +/- SD 27 +/- 3 yr; 78.4 +/- 0.7 kg) completed square-wave transitions from unloaded cycling to work rates equivalent to 100, 110, and 120% of the work rate at [latin capital V with dot above]O2peak (W-[latin capital V with dot above]O2peak) after no prior exercise (control, C) and 10 min after a 6-min bout of heavy exercise at 50% Δ (HE; half-way between the gas exchange threshold (GET) and [latin capital V with dot above]O2peak), in a counterbalanced design. Results: Blood [lactate] was significantly elevated before the onset of the perimaximal exercise bouts after prior HE (2.5 vs 1.1 mM; P < 0.05). Prior HE increased time to exhaustion at 100% (mean +/- SEM. C: 386 +/- 92 vs HE: 613 +/- 161 s), 110% (C: 218 +/- 26 vs HE: 284 +/- 47 s), and 120% (C: 139 +/- 18 vs HE: 180 +/- 29 s) of W-[latin capital V with dot above]O2peak, (all P < 0.01). [latin capital V with dot above]O2 was significantly higher at 1 min into exercise after prior HE at 110% W-[latin capital V with dot above]O2peak (C: 3.11 +/- 0.14 vs HE: 3.42 +/- 0.16 L[middle dot]min-1; P < 0.05), and at 1 min into exercise (C: 3.25 +/- 0.12 vs HE: 3.67 +/- 0.15; P < 0.01) and at exhaustion (C: 3.60 +/- 0.08 vs HE: 3.95 +/- 0.12 L[middle dot]min-1; P < 0.01) at 120% of W-[latin capital V with dot above]O2peak. Conclusions: This study demonstrate that prior HE, which caused a significant elevation of blood [lactate], resulted in an increased time to exhaustion during subsequent perimaximal exercise presumably by enabling a greater aerobic contribution to the energy requirement of exercise