Effects of Self-selected or Predetermined Intensity Aerobic Exercise on the Quality of Life of Adolescents with Obesity

This study aimed to compare the effects of aerobic training at self-selected intensity (SIE) and predetermined intensity (PIE) on the health-related quality of life (HRQOL) in adolescents with obesity. Randomized clinical trial conducted with 37 adolescents (boys and girls), 13–18 yr old, at Tanner stages 3–4, and body mass index ≥95th. Eighteen adolescents were randomly assigned to SIE and 19 to PIE. Aerobic training sessions consisted of 35 min of training on a treadmill, three times per week, for 12 wk. SIE group chose the speed/intensity at the beginning of each training session and was able to change it every 5 min. PIE group trained at a PIE of 60%–70% of heart rate reserve. The Pediatric Quality of Life Inventory was used in to measure HRQOL. Twenty-five adolescents completed the experimental protocol (SIE = 13 and PIE = 12). Heart rate during sessions was higher for PIE than SIE. Both groups decreased body mass (SIE from 100.7 ± 21.85 to 92.1 ± 25.20 kg; PIE from 98.9 ± 24.93 to 88.1 ± 12.91 kg; P = 0.01), body mass index (SIE from 37.4 ± 7.24 to 33.7 ± 8.55 kg·m−2; PIE from 37.3 ± 7.15 to 33.4 ± 5.48 kg·m−2; P < 0.01), and sum of skinfold thickness (SIE from 180.4 ± 26.33 to 163.5 ± 25.04 mm; PIE from 174.00 ± 28.55 to 149.00 ± 32.10 mm; P = 0.01) without group differences. PIE improved HRQOL at social functioning (PIE from 70.0 ± 15.9 vs to 80.9 ± 13.75; P = 0.02). Compared with PIE exercise, SIE did not induce additional improvements in HRQOL in adolescents with obesity.