ABSTRACT
           Background and objectives: Studies have shown that exercise can affect hormone secretion and some metabolic and endocrine functions. The aim of this study was to assess the effect of eight weeks of aerobic training on thyroid hormones and quality of life in obese postmenopausal women.
           Methods: In this semi-experimental study, 21 obese (body mass index >30 Kg/m²) women aged between 35 and 45 were randomly divided into an experimental (n=10) group and a control group (n=11). The subjects in the experimental group performed 30-60 minutes of aerobic exercise at 65-75% of maximum heart rate, three times a week, for eight weeks. Level of thyroid hormones and quality of life subscales were compared within and between the groups. Statistical analysis was performed at significance level of 0.05.
           Results: After the eight-week exercise program, thyroxine, triiodothyronine and thyrotropin releasing hormone levels increased significantly, and thyroid releasing hormone level decreased significantly (P=0.001). The exercise program also had significantly positive effects on quality of life and its occupational, sexual and emotional subscales in obese postmenopausal women.
           Conclusion: Aerobic exercise causes a significant increase in levels of thyroxine, triiodothyronine and thyrotropin releasing hormone and some subscales of quality of life. It also causes a significant decrease in thyroid releasing hormone level, which indicates the effect of exercise on hormone secretion.
           KEYWORDS: Thyroid hormones, Obese, Quality of life, Aerobic training.