The relationship between power and the time to achieve VO2max

Purpose: The severe exercise intensity domain may be defined as that range of work rates over which V(over dot)O-2max can be elicited during constant-load exercise. The purpose of this study was to help characterize the V(over dot)O-2 response within this domain. Methods: Eleven participants performed cycle ergometer exercise tests to fatigue at several discrete work rates between 95% and 135% of die maximum power (P-max) achieved during an incremental exercise test. Results: As previously demonstrated, the relationship between power and time to fatigue was hyperbolic. The asymptote of power (critical power. P-critical) was 198 +/- 44 W. The rapidity of the V(over dot)O-2 response increased systematically at higher work rates such that the relationship between power and time to V(over dot)O-2max was also well fit by a hyperbola. The power asymptote of this relationship (196 +/- 42 W) was not different from P-critical (P > 0.05). The two hyperbolic relationships converged at 342 +/- 70 W (136% P-max). Conclusion: These data suggest that, for this population of male and female university students. the upper boundary of the severe exercise intensity domain is similar to136% P-max This upper boundary is the highest work rate fur which exercise duration is prolonged sufficiently (in this study, 136 +/- 17 s) to allow V(over dot)O-2 to rise to its maximal value. The lower boundary for severe exercise is just above P-critical, which is the highest work rate that is sustainable for a prolonged duration and that will not elicit V(over dot)O-2max.