Effects of unsupervised campus HIIT on fitness and sleep in sedentary male students: a randomized controlled trial.

BACKGROUND: Sedentary behavior and poor sleep quality are prevalent among university students and are associated with reduced cardiorespiratory fitness. This randomized controlled trial evaluated the effects of a six-week, campus-based running high-intensity interval training (HIIT) program on physical fitness, sleep quality, and body composition in sedentary male university students. METHODS: Fifty-six participants (age 21.6 ± 2.4 years) completed the study and were analyzed (HIIT group, n = 28; control group, n = 28). The unsupervised six-week intervention consisted of three weekly sessions of repeated 1-min high-intensity running bouts with recovery periods. Physical fitness, sleep quality, and body composition were assessed. Within- and between-group comparisons were conducted using t-tests, the Wilcoxon signed-rank test, or the Mann–Whitney U test, depending on data normality. Group-by-time interactions were examined using generalized estimating equations. RESULTS: Significant group-by-time interactions were observed for VO2max (β = − 6.63, 95% CI − 8.77 to − 4.49, p < 0.001, d = 1.019) and balance (β = − 23.11, 95% CI − 41.16 to − 5.06, p = 0.012, d = 0.544), with the HIIT group showing significant improvements (19.24% and 49.64%, respectively), whereas controls did not. While the group-by-time interaction for sleep quality was not significant, a favorable trend toward within-group improvement was observed in the HIIT group (− 0.57 points, − 12.15%, p = 0.082, d = 0.270), whereas no such trend occurred in the control group (0.07 points, 1.28%, p = 0.892, d = 0.029). No significant changes were observed for the remaining physical fitness indicators or body composition. CONCLUSIONS: A six-week, unsupervised campus-based HIIT running program improved cardiorespiratory fitness and balance while showing good adherence and safety in sedentary male university students, confirming its feasibility in a real-world setting. Potential benefits for sleep quality warrant validation in larger randomized trials. TRIAL REGISTRATION: ClinicalTrials.gov (NCT07256847).