High Intensity Interval Training (HIIT) has been pointed as an efficient method for cardiorespiratory enhancement in comparison with traditional continuous aerobic training (CAT). Such difference is believed to be explained by assessing the energy expenditure of training sessions. Hence, in order to test this hypothesis, it was realized an acute intervention in recreationally active young men during three experimental conditions with a cross-over design. Energy expenditure results indicate that it is highly correlated with exercise volume, and even though energetic systems contribution during HIIT and CAT sessions were different, total caloric expenditure were similar between exercises sessions.