Document Type : Research Paper I Open Access I Released under (CC BY-NC) license
Authors
1 Ph. D student, Department of Exercise Physiology, Bo.c. , Islamic Azad University, Borujerd, Iran.
2 Department of Physical Education and Sports, Faculty of Humanities, Ayatollah Borujerdi University, Borujerd, Iran.
3 Department of Sport Sciences, Faculty of Humanities, Razi university, Kermanshah, Iran.
Abstract
Introduction:
Ambient temperature and exercise type influence leptin concentration and metabolic status. This study aimed to investigate the effect of six weeks of high-intensity interval training (HIIT) in cold temperature on insulin resistance index and serum leptin levels in obese men.
Methods:
The sample included 32 young obese men (age: 22.2 ± 2.9 years; BMI: 31.4 ± 1), randomly divided into four groups: TR22 (training at 22°C), TR10 (training at 10°C), C22 (rest at 22°C), and C10 (rest at 10°C). TR22 and TR10 groups performed HIIT on a treadmill for six weeks, three sessions per week, consisting of 8–10 intervals of 1-minute running at 85–95% of heart rate reserve, with 1-minute active rest at 60–70%. Leptin, insulin, glucose, anthropometric indices, and HOMA-IR were measured before and after the intervention.
Results:
In the TR10 group, after six weeks of training in cold, significant decreases were observed in leptin (P=0.04), insulin (P=0.039), glucose (P=0.034), weight (P=0.042), and body fat percentage (P=0.016). These changes were not observed in other groups, including TR22. Additionally, in TR10, a significant correlation was found between reductions in body fat percentage and leptin (P=0.031) and insulin (P=0.039). No changes in HOMA-IR were detected.
Conclusion:
HIIT in cold air has a greater effect on reducing leptin compared to normal temperature. HIIT at both temperatures had no significant impact on HOMA-IR. Reductions in leptin and insulin were associated with decreased body fat percentage
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