Evaluation of the relationships between aerobic fitness and O₂ uptake to heart beat during an incremental exercise tests

Abstract

Maximal exercise capacity (W_max) and anaerobic threshold (A_T) are important tools used non-invasively to evaluate aerobic fitness levels and clinically possible risk. It has been shown that O₂ uptake to heartbeat ratio (O₂ pulse) at the maximal exercise test is an important parameter used to evaluate fitness levels of the subjects. However, O₂ pulse at the anaerobic threshold and fitness status of the subjects has not been described yet. In this study, we comparatively evaluated the fitness levels and O₂ pulse at A_T and at W_max in healthy young male subjects during an incremental exercise test. A total of 20 healthy male performed an incremental exercise test (15 W/min) to exhaustion on a cycle ergometer. Ventilatory and pulmonary gas exchange parameters were measured breath-by-breath using the metabolic gas analyser and turbine volume-meter. A_T has been estimated using the V-slope method. The work rate at AT and Wmax was found to be 135 ± 4 W and 225 ± 4 W, respectively. O₂ pulse was found to be 13.49 ± 0.3 ml/beat at A_T and 16.53 ± 0.31 ml/beat at W_max. There was a significant positive correlation between W_max and O₂ pulse R = 0.75184 (P < 0.05). In addition, there was a significant correlation between work production capacity for each kg of body weight and O₂ pulse R = 0.68811 (p < 0.0001). We have shown that O₂ pulse at A_T can also be used to evaluate the fitness status. Thus, considering effective fitness measurement at the A_T, investigators should be avoiding difficulty in maximal exercise performance.

Keywords: O₂ pulse, exercise, fitness.

This article is published under the terms of the Creative Commons Attribution License 4.0