Can short-term high-intensity intermittent training reduce adiposity?

Purpose To compare the effects of 6 weeks of high-intensity intermittent training (HIIT) and moderate intensity continuous exercise (MICT-control group) on body composition, hunger and food intake. Methods Twenty-three previously untrained women (28.43 ± 12.53 years) were randomly assigned to a HIIT ( n = 11) or MICT group ( n = 12). The HIIT group performed 15 1-min bouts at 90 % of maximum heart rate (HRmax) interspersed by 30-s active recovery (60 % HRmax). The MICT group performed a continuous exercise at 70 % HRmax equalizing the training load method proposed by Edwards (1993) to a similar value achieved by the HIIT group. Training for both groups was performed three times per week for 6 weeks. All subjects performed the Astrand cycloergometer test to estimate maximal oxygen consumption (VO 2max ) 1 week before and after the training period, as well as body composition, which was estimated through circumferences and skinfold thicknesses. For all training sessions heart rate, visual scale of hunger and internal load were recorded. In the first and last week of training subjects were asked to record a 24-h food diary for 3 days. Results Both training induced significant pre- to post-decreases for fat mass, fat percentage, waist circumference and sum of seven skinfolds. However, only the sum of skinfolds differed between protocols with a higher mean percentage change for HIIT compared to the MICT. As expected, estimated VO 2max increased in both groups. There were no differences for hunger, energy intake and body mass. Conclusions HIIT resulted in a greater fat loss compared to moderate continuous aerobic training.