Maximal exercise capacity (W[subscript max]) and anaerobic threshold (A[subscript T]) are important tools used non-invasively to evaluate aerobic fitness levels and clinically possible risk. It has been shown that O[subscript 2] uptake to heartbeat ratio (O[subscript 2] pulse) at the maximal exercise test is an important parameter used to evaluate fitness levels of the subjects. However, O[subscript 2] 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 O[subscript 2] pulse at A[subscript T] and at W[subscript 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. AT has been estimated using the V-slope method. The work rate at A[subscript T] and W[subscript max] was found to be 135 ± 4 W and 225 ± 4 W, respectively. O[subscript 2] pulse was found to be 13.49 ± 0.3 ml/beat at A[subscript T] and 16.53 ± 0.31 ml/beat at W[subscript max]. There was a significant positive correlation between W[subscript max] and O[subscript 2] 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 O[subscript 2] pulse R = 0.68811 (p < 0.0001). We have shown that O[subscript 2] pulse at A[subscript T] can also be used to evaluate the fitness status. Thus, considering effective fitness measurement at the A[subscript T], investigators should be avoiding difficulty in maximal exercise performance.