Azarbaijan Shahid Madani University Journal of Applied Health Studies in Sport Physiology 2676-6507 Articles in Press 2025 05 31 The Effect of High-Intensity Interval Training (HIIT) on Serum Oncostatin M concentrations, Insulin Resistance, and Body composition indices in Overweight and Obese Women The Effect of High-Intensity Interval Training (HIIT) on Serum Oncostatin M concentrations, Insulin Resistance, and Body composition indices in Overweight and Obese Women 14961 10.22049/jahssp.2025.30518.1734 FA Ramin Amirsasan Professor in Depatment of Exercise Physiology, Faculty of Physical Education and Sports Sciences, University of Tabriz, Tabriz, Iran. Shabnam Akbarzadeh PhD Student in Exercise Physiology, Faculty of Physical Education and Sports Sciences, University of Tabriz, Tabriz, Iran. 0000-0003-1464-8564 Javad Vakili Associate Professor in Depatment of Exercise Physiology, Faculty of Physical Education and Sports Sciences, University of Tabriz, Tabriz, Iran. Journal Article 2025 04 15 Transforming white adipose tissue (WAT) into brown adipose tissue (BAT) to increase whole body metabolism, reduce weight, and improve insulin sensitivity is an interesting strategy to combat obesity. Oncostatin M (OSM) is a hormone that is closely related to BAT activity and WAT browning. Therefore, the aim of this study was to determine the effect of eight weeks of high-intensity interval training (HIIT) on serum OSM levels, insulin resistance, and body composition indices in overweight and obese women. Methods: This was a quasi-experimental study with a pretest-posttest design in which 25 overweight and obese women were randomly divided into two groups: a control group (n=13) and a HIIT group (n=12). HIIT training was performed for eight weeks (three sessions per week). Blood samples were collected in two stages, before and 48 hours after the last training session (after 10 weeks of training) to measure OSM, insulin resistance, and lipid profile. Data were analyzed using paired t-test and analysis of covariance at a significance level of less than 0.05. Results: HIIT training program resulted in significant reductions in serum OSM (p=0.000), insulin resistance (p=0.000), triglycerides (p=0.01), total cholesterol (p=0.01), LDL (p=0.01), VLDL (p=0.01), weight (p=0.000), BMI (p=0.001), WHR (p=0.000), and body fat percentage (p=0.000). Conclusion: Eight weeks of HIIT can improve insulin resistance index, body composition, and lipid profile in overweight and obese women by reducing serum OSM levels. Transforming white adipose tissue (WAT) into brown adipose tissue (BAT) to increase whole body metabolism, reduce weight, and improve insulin sensitivity is an interesting strategy to combat obesity. Oncostatin M (OSM) is a hormone that is closely related to BAT activity and WAT browning. Therefore, the aim of this study was to determine the effect of eight weeks of high-intensity interval training (HIIT) on serum OSM levels, insulin resistance, and body composition indices in overweight and obese women. Methods: This was a quasi-experimental study with a pretest-posttest design in which 25 overweight and obese women were randomly divided into two groups: a control group (n=13) and a HIIT group (n=12). HIIT training was performed for eight weeks (three sessions per week). Blood samples were collected in two stages, before and 48 hours after the last training session (after 10 weeks of training) to measure OSM, insulin resistance, and lipid profile. Data were analyzed using paired t-test and analysis of covariance at a significance level of less than 0.05. Results: HIIT training program resulted in significant reductions in serum OSM (p=0.000), insulin resistance (p=0.000), triglycerides (p=0.01), total cholesterol (p=0.01), LDL (p=0.01), VLDL (p=0.01), weight (p=0.000), BMI (p=0.001), WHR (p=0.000), and body fat percentage (p=0.000). Conclusion: Eight weeks of HIIT can improve insulin resistance index, body composition, and lipid profile in overweight and obese women by reducing serum OSM levels. https://jahssp.azaruniv.ac.ir/article_14961_9c9c3a9dd00317aee2e0719ef2f7e4df.pdf