Cardiovascular Effects of Aerobic Exercise With Self-Selected or Predetermined Intensity in Adolescents With Obesity.

This study compared the effects of self-selected exercise intensity (SEI) versus predetermined exercise intensity (PEI) on blood pressure (BP) and arterial stiffness in adolescents with obesity. A total of 37 adolescents, 14.7 (1.6) years old, body mass index ≥95th percentile were randomly allocated into SEI (n = 18; 12 boys) or PEI (n = 19; 13 boys). Both groups exercised for 35 minutes on a treadmill, 3 times per week, for 12 weeks. The SEI could set the speed at the beginning of the sessions and make changes every 5 minutes. The PEI adolescents were trained at an intensity set at 60% to 70% of heart rate reserve. Brachial and central BP, pulse pressure, augmentation index, and carotid-femoral pulse wave were determined at baseline and after 12 weeks. Both groups reduced brachial systolic BP (SEI, Δ = -9 mm Hg; PEI, Δ = -4 mm Hg; P < .01), central systolic BP (SEI, Δ = -4 mm Hg; PEI, Δ = -4 mm Hg; P = .01), and central pulse pressure (SEI, Δ = -4 mm Hg; PEI, Δ = -3 mm Hg; P = .02) without differences between groups. No changes in the augmentation index and carotid-femoral pulse wave were observed in either group. The SEI induced similar changes in various cardiovascular outcomes compared with PEI in adolescents with obesity.

Aerobic Training Performed at Ventilatory Threshold Improves Psychological Outcomes in Adolescents With Obesity.

BACKGROUND: Physical activity may be as effective as some drugs for improving psychological outcomes; however, vigorous exercise may be needed for improving these outcomes in adolescents with obesity. The aim of this study is to examine the effects of low- and high-intensity training on self-esteem and symptoms of depression and anxiety in adolescents with obesity. METHODS: A total of 62 pubertal adolescents with obesity (age 15 [1.5] y, body mass index 34.87 [4.22] kg/m2) were randomized into high-intensity group (HIG, n = 31) or low-intensity group (LIG, n = 31) for 24 weeks. All participants also received nutritional, psychological, and clinical counseling. Body composition and measures of depressive symptoms, anxiety, and self-esteem were assessed at baseline and after 24 weeks. RESULTS: Depressive symptoms decreased significantly in both HIG (d = 1.16) and LIG (d = 0.45) (P ≤ .01). Trait anxiety decreased after 24 weeks for HIG (d = 0.81, P = .002) and LIG (d = 0.31, P = .002). No changes were observed in state anxiety or self-esteem. CONCLUSIONS: Results from the present study demonstrate that 24 weeks of multidisciplinary intervention improves depression and anxiety symptoms in adolescents with obesity; however, the magnitude of changes is higher in HIG compared with LIG.

Aerobic training performed at ventilatory threshold improves liver enzymes and lipid profile related to non-alcoholic fatty liver disease in adolescents with obesity.

BACKGROUND: Despite the positive effects of high-intensity training on weight management and health-related outcomes, it is postulated that high-intensity training may also induce oxidative stress, increasing hepatic damage. AIM: The aim of this study was to compare the effects of low versus high-intensity training on biomarkers related to non-alcoholic fatty liver disease (NAFLD) in adolescents with obesity. METHODS: For this study 107 adolescents (15 ± 1 years) with obesity (BMI = 34.7 ± 4.1 kg/m2) were randomized into High-Intensity Training (HIT, n = 31), Low-Intensity Training (LIT, n = 31) or Control Group (CG, n = 45). Adolescents from HIT and LIT received nutritional, psychological and clinical counseling. Blood lipids, Castelli risk index, glucose, insulin and hepatic enzymes were measured at baseline and after 12 weeks. RESULTS: Castelli risk index 1 was reduced in all groups ( p < 0.001) with moderate effect size ( d) for HIT ( d = 0.62) and LIT ( d = 0.66). Castelli risk index 2 also decreased ( p < 0.001 for all groups; HIT d = 0.65; LIT d = 0.79). High-density lipoprotein increased in all groups ( d = 0.25 and d = 0.18 in HIT and LIT), while alanine aminotransferase tended to reduce ( p = 0.062) in HIT ( d = 0.34) and LIT ( d = 0.73) and aspartate aminotransferase decreased ( p = 0.024) in both HIT ( d = 0.24) and LIT ( d = 0.45). There were no changes in glucose, insulin and insulin resistance. CONCLUSION: Both high and low-intensity training improved biomarkers related to NAFLD. Thus, high-intensity training can be a safe and effective alternative to prevent and treat NAFLD in adolescents with obesity.

Rating of Perceived Exertion During Circuit Weight Training: A Concurrent Validation Study.

The aim of this study was to determine whether rating of perceived exertion (RPE) is a valid method to control the effort during the circuit weight training (CWT) in trained men. Ten men (21.3 ± 3.3 years) with previous experience in resistance training (13.1 ± 6.3 months) performed 3 sessions: 1 orientation session and 2 experimental sessions. The subjects were randomly counterbalanced to 2 experimental sessions: CWT or multiple-set resistance training (control). In both sessions, 8 exercises (bench press, leg press 45°, seated row, leg curl, triceps pulley, leg extension, biceps curl, and adductor chair) were performed with the same work: 60% of 1 repetition maximum, 24 stations (3 circuits) or 24 sets (3 sets/exercise), 10 repetitions, 1 second in the concentric and eccentric phases, and rest intervals between sets and exercise of 60 seconds. Active muscle RPEs were measured after each 3 station/sets using the OMNI-Resistance Exercise Scale (OMNI-RES). In this same time, blood lactate was collected. Compared with baseline, both levels of blood lactate and RPE increased during whole workout in both sessions, the RPE at third, 23rd, and 27th minute and the blood lactate at third, seventh, 11th, 15th, 27th, and 31st minute were higher in multiple set compared with CWT. Positive correlation between blood lactate and RPE was observed in both experimental sessions. The results indicated that the RPE is a valid method to control the effort during the CWT in trained men and can be used to manipulate the intensity without the need to perform invasive assessments.