Background: The aim of this study was to investigate the relationship between the serum level of lactate and glucose with oxygen saturation, maximal heart rate and VO2max in response to L-carnitine during exhaustive exercise in young active men. Materials and Methods: In this study, 10 young men (age: 26.4±0.96 years, height: 173.9±9.45 cm and weight: 71.8±5.36 kg) were participated. The subjects performed two sessions of the Bruce test. Serum levels of lactate, glucose, oxygen saturation (%SO2), VO2max, HRmax were recorded before, immediately and 4min after the exhaustive exercise. Results: The results showed that in the supplement group there was a significant relationship between the serum levels of lactate and VO2max 4min after the termination of the exercise. Also, there was a significant relationship between the serum levels of glucose and %SO2 immediately after the exercise (P<0.05). There was no significant relationship between the other factors. Conclusions: According to the results of this study, the L-carnitine supplementation has positive effects on the relationship between serum levels of lactate with VO2max and serum levels of glucose and %SO2 immediately after the exhaustive exercise. So, the L-carnitine supplementation through increasing the exhaustion threshold has a significant effect on aerobic power in performing the intensive exhausting activities.