PURPOSE: Intermittent training has been applied in athlete training for 100 years more. In the last 10 years, it attained additional application in the enhancement of physical fitness and the rehabilitation of multiple chronic diseases. Moreover, many evidence suggests that when compared with steady state exercise, intermittent training can result in comparable or greater improvement in heart failure, diabetes, obesity and other chronic diseases. However, due to the differences of exercise workload (exercise duration, intensity and pattern) in most of researches, it is hard to assert which one is better between continuous and intermittent exercise when faced to some certain of health issues. Therefore, this study aimed to compare the energy consumption and substrate utilization between continuous and intermittent exercise with equal workload during and post exercise, and analyze their relationship with the activity of autonomic nervous system.
METHODS: 12 male students (24.2±1.2 years old), randomly performed 3 tests with 1 week interval: Control (C; rest), continuous exercise (CE; 65% VO2max, 40 min), and intermittent exercise (IE; 85% VO2max, 4min; 45% VO2max, 4min; 5 sessions). Exercise is performed on treadmill with equal workload. In the period of pre- (30 min), during- (40min) and post-exercise (every 1 hour for 8 hours), respiratory metabolism, heart rate variability (HRV), blood pressure, and body temperature were monitored. Paired simple t-tests were used for statistical analysis. This study was funded by two fund from Guangdong (2013B031600003) and Guizhou (2014-7455) Science and Technology Department.
RESULTS: The energy expenditure (EE) and substrate utilization during exercise showed no significant difference between IE and CE. However, IE had higher total 8-hour’s EE during post-exercise (1.1-fold, p<0.05, ES=1.85) with much fat oxidation (1.2-fold, p<0.05, ES=2.63) and significant rising value of LF/HF of HRV analysis (1.7-fold, p<0.01, ES=4.34). The total energy consumption (during exercise plus post-exercise) in IE is higher than CE (1.05-fold, p<0.05, ES=2.17).
CONCLUSIONS: High intensity intermittent exercise can induce much fat oxidation during the period of post-exercise and raise total exercise consumption, which is probably relevant to enhanced sympathetic regulation.