Substrate oxidation during incremental exercise in young women: The effects of 2-week high intensity interval training

BACKGROUND: The objective of this study was to investigate the effects of very low volume (in terms of the number of training days and load number in every session) of a high-intensity interval training (HIIT) program on substrate oxidation during incremental exercise until exhaustion in recreationally active women. METHODS: Sixteen young women (N.=8 training; N.=8 controls) voluntarily participated in this study. Before the experiment, peak and mean power outputs were measured by the Wingate Anaerobic Test (WAT), VO2max, the maximal fat oxidation rate (MFO) and Fatmax intensity and were not different between the groups (P>0.05). The training group completed two weeks of HIIT (10 sessions), including 2 WATs in every training session. RESULTS: After the experiment, peak and mean power, VO2max, exhaustion time and CHOpeak increased in the training group. Nevertheless, the MFO and Fatmax intensity values did not change. CONCLUSIONS: These results demonstrated that a 2-week HIIT increased aerobic and anaerobic capacity without any change in the MFO and Fatmax during maximal exercise.