For busy individuals seeking to establish an exercise habit, weight-bearing exercise-based high-intensity interval training (HIIT) is a time-efficient option. Although single sessions have been shown to improve postprandial blood glucose, whether unsupervised HIIT supports long-term adherence remains unclear. Therefore, this study compared the effects of eight weeks of supervised HIIT and moderate-intensity continuous training (MICT) on adherence and blood glucose indicators. We recruited 46 healthy young adults with no exercise habits, and low to moderate physical activity. After a two-week pre-measurement period, participants were randomly assigned to a HIIT group that performed weight-bearing exercise-based HIIT three times a week for eight weeks without supervision, an MICT group that performed running three times a week for eight weeks without supervision, or a control group that did not change their lifestyle. The intervention period was followed by a two-week post-measurement period for between-group and pre- and post-intervention comparisons. The primary outcome was exercise adherence, assessed based on a self-report and supplemented with a tri-axial accelerometer and glycemic index. Adherence was significantly higher in the HIIT group (60.6 ± 25.7%) than in the MICT group (27.9 ± 22.3%). No significant differences in glycemic index were observed either pre- to post-intervention or between groups. Overall, unsupervised HIIT produced greater adherence than comparable running, but did not alter blood glucose levels in healthy young adults.
Nakayama et al. (Thu,) studied this question.