Effects of two different eight-week walking programs on insulin resistance and ER stressrelated markers in pre-menopausal women / Premenopozal kadınlarda 8 haftalık farklı şiddetteki yürüyüş antrenmanlarının insülin direnci ve ER stresiyle ilişkili markerler üzerine etkileri

Abstract

Abstract Objective: The relationship between exercise and endoplasmic reticulum (ER) stress, insulin resistance, and obesity is a new field of research. To our knowledge, there are no studies examining the effects of walking exercises on ER stress related markers and insulin resistance in pre-menopausal women. To examine the effect of two different eight-week walking programs on the tumor necrosis factor-alpha (TNF-α), Fetuin-A (α2 - Heremans Schmid glycoprotein), c-Jun N-terminal kinase-1 (JNK-1) and retinol- binding protein-4 (RBP-4), the related markers of ER stress and insulin resistance in pre-menopausal women. Methods: Exercise groups (moderate tempo walking group; MTWG; n=11; brisk walking group BWG; n=12) walked five days a week, starting from 30 minutes, gradually increasing up to 51 minutes. BWG walked at ~70-75% and MTWG at ~50-55 of HRRmax. Body mass index (BMI), body fat percentage (%), VO2max, serum TNF-α, Fetuin-A, JNK-1, RPB-4, blood lipids, and insulin resistance levels were determined before and after the intervention. Results: VO2max increased in both exercise groups favoring BWG; RBP-4 decreased in both exercise groups (p<0.05). Serum TNF-α and, TG (p<0.05), BMI and percent body fat (p<0.01), and insulin levels reduced significantly in BWG (p<0.05). The reductions observed in both exercise groups in insulin resistance, and the increases determined in the negative levels of JNK-1 in BWG may be clinically important. Conclusion: Both type of walking resulted in similar positive effects on RBP-4. The reduction observed in TNF-α, RBP-4, and the increases in the negative levels of JNK-1 in BWG show the positive effects of brisk walking on ER stress. The reduction in insulin resistance in relation to the possible reductions in ER stress and apoptosis in BWG may be more effective to prevent metabolic diseases.