Effects of aerobic, resistance, and combined training on thyroid function and quality of life in hypothyroidism. A randomized controlled trial

Purpose: This study aimed to compare the effects of aerobic, resistance, and combined exercises on thyroid function, lipid profile, exercise capacity, and quality of life (QoL) in hypothyroid women. Methods: Sixty women aged 35 to 45 with clinical hypothyroidism were randomized to four equal groups: aerobic training (AT), resistance training (RT), combined AT/RT, and control groups. All exercises were performed at low to moderate intensity, three days per week, and for 12 weeks. Patients in all groups were on levothyroxine therapy. Outcome measures were free thyroxin (T4), thyroid stimulating hormone (TSH), lipid profile, estimated maximal oxygen consumption (VO2 max) and QoL assessed by the 12-item Short Form (SF-12) Health Survey. Results: All exercise groups showed significant improvements in all outcome measures compared to the baseline and the controls (p < 0.05). The combined AT/RT group showed more significant improvements in TSH and the mental component summary score of the SF-12 compared to the AT and RT groups (p < 0.05). The AT group showed the most significant improvement in estimated VO2 max, followed by the combined AT/RT and then the RT group. Non-significant differences were found between exercise groups in T4, blood lipids, and the physical component summary score of the SF-12 (p > 0.05). Conclusion: In women with hypothyroidism on levothyroxine treatment, all AT, RT, and combined AT/RT could equally improve T4 levels, lipid profile, and physical health-related QoL. However, the combined AT/RT could induce the greatest improvements in TSH and mental health-related QoL, while the AT could have the greatest impact on exercise capacity in these patients. Trial registration: Pan African Clinical Trial Registry (PACTR), retrospective, PACTR202305810673587.