Aerobic Fitness Level Modulates the Effects of Prior Supramaximal Exercise on Pulmonary O2 Response During Moderate-Intensity Exercise

The aim of this study was to analyze the influence of aerobic fitness on the effects of prior exercise on O2 response during subsequent moderate-intensity exercise. After determination of the lactate threshold (LT) and maximal O2 (V.O2max), 14 untrained subjects (UG) and 14 well-trained cyclists (TG) performed on different days and in random order, rest to moderate-intensity exercise transitions (6 minutes at 80% of LT), preceded by either no prior exercise or prior supramaximal exercise (PSE: two bouts of 1 minute at 120% of V.O2max, with a 1-minute rest in between). Baseline V.O2 was significantly increased (p < 0.05) by PSE in both groups (UG: 0.39 ± 0.06 vs. 0.51 ± 0.15 L·min−1; TG: 0.37 ± 0.06 vs. 0.58 ± 0.14 L·min−1). In the TG group, the steady state O2 was significantly increased by PSE (TG: 2.21 ± 0.38 vs. 2.07 ± 0.27 L·min−1, p < 0.05; UG:1.60 ± 0.27 vs. 1.60 ± 0.29 L·min−1, p > 0.05). It can be concluded that aerobic fitness level influences the effects of PSE on O2 response during moderate-intensity exercise.