Greater effects of high- compared with moderate-intensity interval training on thyroid hormones in overweight/obese adolescent girls

• Published in: Hormone molecular biology and clinical investigation Vol. 41; no. 4; pp. 355 - 361
• Main Authors: Abassi, Wissal, Ouerghi, Nejmeddine, Ghouili, Hatem, Haouami, Salma, Bouassida, Anissa
• Format: Journal Article
• Language: English
• Published: Germany De Gruyter 01.12.2020; Walter de Gruyter GmbH
• Subjects: Body weight; insulin-resistance; intermittent training; Obesity; Overweight; Teenagers; Thyroid hormones; thyroid stimulating hormone; thyroxine; training intensity; intermittent training; thyroxine; training intensity; insulin-resistance; thyroid stimulating hormone
• DOI: 10.1515/hmbci-2020-0031
• ISSN: 1868-1883

To investigate the effects of 12-week high-intensity- (HIIT) moderate-intensity-interval training (MIIT) on thyroid stimulating hormone (TSH) and thyroxine (T4) and insulin-resistance in overweight/obese adolescent girls. Twenty four adolescent girls (age 16.5±1.36 yrs) were randomly allocated into three groups: (1) HIIT (2 blocks per session of 6-8 bouts of 30 s runs at 100-110% maximal aerobic speed (MAS), with 30 s active recovery between bouts at 50% MAS; n=8), (2) MIIT (2 blocks per session of 6-8 bouts of 30 s runs at 70-80% MAS, with 30 s active recovery between bouts at 50% MAS; n=8) and (3) control group (no exercise, n=8). Each training groups engaged in three sessions per week during three months. Anthropometric parameters, aerobic capacity, homeostasis model assessment index for insulin resistance (HOMA-IR) as well as plasma TSH and T4 levels were assessed in all subjects before- and after-training. Following both training programs, body mass, body mass index Z-score, waist circumference and body fat decreased, while aerobic capacity increased. However, TSH and T4 concentrations decreased only after the HIIT (-30.47%, p<0.05, ES=1.42 and -12.86%, p<0.05, ES=1.18; respectively). The HOMA-IR decreased in both training groups (-26.25%, p<0.05, ES=1.87 for MIIT and -21.72%, p<0.05, ES=2.14 for HIIT). Twelve weeks of HIIT was effective in reducing circulating TSH and T4 levels, unlike MIIT, in overweight/obese adolescent girls. These findings indicated that the stimulation of pituitary-thyroid function is more sensitive to training intensity than training duration. Further studies are needed to confirm this conclusion.