Stroke volume responses may be related to the gap between peak and maximal O2 consumption

BACKGROUND: Although several studies have focused on maximal O2 uptake (V O2max) measured by a verification phase following the determination of peak O2 uptake (V O2peak) by a graded exercise test, an explanation for the underlying mechanisms of the difference between V O2peak and confirmed V O2max is scant. OBJECTIVE: To explore the hypothesis that when the difference between V O2peak and V O2max (ΔV O2) increases, the gap between peak stroke volume (SVpeak) and SV level corresponding to V O2peak velocities (ΔSV) grows. METHODS: Nine moderately to well-trained male athletes (V O2max: 60.2 ± 7 mL · min−1 · kg−1) volunteered to take part in the study. Following familiarization session, volunteers were asked to perform submaximal and maximal graded exercise tests. Then, constant-loading SVpeak tests (using wattages in a range from 40–100% of V O2peak) and verification phase (using wattages corresponding with 100–110% of V O2peak) were conducted in a climatic chamber. RESULTS: The ΔV O2 was well correlated with ΔSV (Pearson r = 0.89; p 0.001). The mean SVpeak of participants corresponded to 60.3± 18% of V O2peak. V O2max was significantly greater (11.2%) than V O2peak (60.2± 7 vs. 54.2± 8.1 mL · min−1 · kg−1) (p 0.01). CONCLUSIONS: V O2peak and V O2max differences may be related to the gap between SVpeak and SV at V O2peak.