Objectives: To compare the effects of self-selected and predetermined intensity on sleep quality and duration, daytime sleepiness, and sleep efficiency of adolescents with obesity after 12 weeks of aerobic training. Material and Methods: Thirty-seven adolescents (12 girls), 13-18 years old, with obesity (BMI = 95th) were randomized into a predetermined intensity group (PIG), exercise intensity around 60-70% of heart rate reserve; or self-selected intensity group (SIG), the adolescents chose the speed/intensity at the beginning of each session and were able to change it every 5 minutes. The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were used to assess sleep outcomes. Results: No differences were observed for PSQI [0.00 ± 2.00 vs 1.38 ± 2.7; p=0.195; d=0.60 (moderate effect)], sleep duration [-0.95 ± 1.2 vs -0.35 ± 1.6; p=0.358; d=0.41 (small effect)], ESS [(2.10 ± 3.9 vs 1.15 ± 4.5; p=0.195; d=0.23 (small effect)], and sleep efficiency [(81.5 ± 24.0 vs 79.4 ± 17.0; p=0.8.14; d=0.10 (trivial effect)] for the PIG and SIG groups, respectively. Conclusion: Aerobic training at a self- selected or predetermined intensity does not modulate sleep quality, sleep duration and efficiency, and daytime sleepiness, independent of intensity.
