University of Guilan Metabolism and Exercise 2322-2867 Articles in Press 2026 06 10 effect of 12 weeks of intense interval training on serum TSH levels and health-related physical fitness indices in female patients with hypothyroidism. effect of 12 weeks of intense interval training on serum TSH levels and health-related physical fitness indices in female patients with hypothyroidism. 9694 10.22124/jme.2026.30688.411 FA Fatemeh Sheikhuche Department of Sport Sciences, Faculty of Education and Psychology, Shahid Madani University of Azerbaijan, Tabriz, Iran. Roghayeh Fakhrpour Department of Sport Sciences, Faculty of Education and Psychology, Shahid Madani University of Azerbaijan, Tabriz, Iran. Yousef Saberi Department of Sport Sciences, Faculty of Education and Psychology, Shahid Madani University of Azerbaijan, Tabriz, Iran. Journal Article 2025 08 14 Introduction: The present study aimed to determine the effect of high-intensity interval training on serum TSH levels and health indicators in women with autoimmune thyroid disease. Methods: The present research method was semi-experimental and consisted of pre-test and post-test, and was applied in terms of purpose and field based on the degree of control and level of supervision. The training protocol consisted of 12 weeks of regular high-intensity interval training (HIIT), three sessions per week, each session lasting an average of 40 minutes, which was performed in a timed session under the supervision of a trainer. After collecting the data in two stages, pre-test and post-test, they were analyzed using SPSS21 software. To determine the normality of the data distribution, the Shapiro-Wilk test was used, and to compare the pre-test and post-test, the ANCOVA test was used to compare the two groups, considering the pre-test as a covariate. Results: After 12 weeks of high-intensity interval training, TSH levels, body fat percentage, body mass index, waist-to-hip ratio, maximum heart rate, resting heart rate, systolic blood pressure, and diastolic blood pressure showed a significant decrease compared to the pre-test and control groups (significance level P Introduction: The present study aimed to determine the effect of high-intensity interval training on serum TSH levels and health indicators in women with autoimmune thyroid disease. Methods: The present research method was semi-experimental and consisted of pre-test and post-test, and was applied in terms of purpose and field based on the degree of control and level of supervision. The training protocol consisted of 12 weeks of regular high-intensity interval training (HIIT), three sessions per week, each session lasting an average of 40 minutes, which was performed in a timed session under the supervision of a trainer. After collecting the data in two stages, pre-test and post-test, they were analyzed using SPSS21 software. To determine the normality of the data distribution, the Shapiro-Wilk test was used, and to compare the pre-test and post-test, the ANCOVA test was used to compare the two groups, considering the pre-test as a covariate. Results: After 12 weeks of high-intensity interval training, TSH levels, body fat percentage, body mass index, waist-to-hip ratio, maximum heart rate, resting heart rate, systolic blood pressure, and diastolic blood pressure showed a significant decrease compared to the pre-test and control groups (significance level P