The Effects of different protocols of isocaloric interval and continuous endurance exercise on fat metabolism

Regular participation in aerobic activities has a positive effect on health. The aim of the present study was to compare the effect of three   iso-caloric   protocols of long-term intermittent exercise, short-term intermittent exercise and continuous exercise on fat metabolism in healthy men.

 Nine healthy men with a mean age (25.62± 2.6 years) participated in this study voluntarily.  In the first session, the subjects sat in the laboratory for 20 minutes, then the first blood sample was taken from their brachial vein. Continuous exercise protocol was performed on the treadmill with an intensity of 65% VO2max and up to a certain calorie intake (250 Kcal). Immediately after the end of the exercise protocol, a second blood sample was taken, then they were rested for an hour and the recovery gases were collected during recovery. After one hour of recovery, a third blood sample was taken. The second and third blood samples of the next two protocols, like the previous protocol, were taken immediately and one hour after the end of the activity. The second session of the long-term intermittent protocol consisted of four-minute interval activity with an intensity of 85% VO2max and four-minute active rest periods with an intensity of 45% VO2max until the energy consumption was equal to the continuous exercise protocol.  The third session consisted of a short-term intermittent protocol with a 30-second to 30-second rest ratio, with a 100% VO2max activity intensity, and a 30% VO2max rest intensity. Data were analyzed using repeated measures and Bonferroni post hoc analysis of variance.  

Results:

 The results showed that exercise, regardless of its type and intensity, has a significant effect on fat oxidation (P = 0.00). The rate of fat oxidation during short-term intermittent protocol was higher than long-term protocol (P = 0.00). it was higher than long-term protocol (P = 0.00) and short-term protocol during continuous activity (P = 0.00). But fat oxidation related to the recovery period of long-term protocol sessions (P = 0.00) and short-term protocol sessions (P = 0.00) was more than continuous protocol.

 It can be concluded that the protocol of long-term intermittent activity for fat metabolism is superior to the other two protocols and this type of activity is recommended for people with reduced body fat.