Pulmonary Ventilation in Relation to Oxygen Uptake and Carbon Dioxide Production During Incremental Load Work

Abstract

The purposes of the present investigation were: (1) to describe the relationships between exercise pulmonary ventilation (VE) and oxygen uptake (VO2) and VE and carbon dioxide production (VCO2), (2) to determine the % VO2 max at the lowest ventilatory equivalent of oxygen (VEO2), and (3) to examine the relationship between the % VO2 max at the lowest VEO2 and maximal aerobic power (VO2 max). During incremental load work, VE increased exponentially in relation to elevations in VO2 and VCO2. Differentiation of the VE to VO2 exponential equation gives the minimum slope of the equation and corresponds to the lowest ventilatory equivalent for oxygen. In our subjects, VO2 max (mean +/- SD) was 3.84 +/- 0.71 l . min-1, and VO2 at the lowest VEO2 was 1.70 +/- 0.32 l . min-1. The VO2 at the lowest VEO2 was 44.3 +/- 4.0% VO2 max (range 37% to 53% VO2 max). The correlation coefficient (r) between VO2 at the lowest VEO2 and VO2 max was 0.90, while the r between % VO2 max at the lowest VEO2 and VO2 max was -0.24.