Metabolic response to 6-week aerobic exercise training and dieting in previously sedentary overweight and obese pre-menopausal women： A randomized trial

Background： The aim of this study was to compare 6 weeks short-term moderate intensity aerobic exercise and dieting on serum metabolomics and cardio-metabolic risk factors in pre-menopausal women. Methods： Ninety previously inactive overweight and obese （BMI 25-35 kg/m2） women （age 41.5 ± 7.6 years） were randomized to either a 6-week Nordic walking exercise program （EX, n = 45） or dietary counseling group （DI, n = 45）. Body composition, serum glucose, insulin and lipids were measured. Serum low-molecular-weight metabolites and lipid constituents were analyzed by nuclear magnetic resonance spectroscopy. Measurements were done at baseline and 7 days after the last training session. Results： Six weeks aerobic exercise program yielded reductions in serum free fatty acids （-34.7%, 95% confidence interval （CI）, -50 to -18, p 〈 0.001）, glucose （-9.6%, 95%CI, -15 to -4, p 〈 0.001） and homeostasis model assessment of insulin resistance （HOMA-IR） （-28.7%, 95%CI, -48 to -10, p = 0.005） without changes in body weight or fat mass. Diet counseling resulted in loss of body weight （1.5%, 95%CI, -2.3 to -0.7, p = 0.001） but no changes in free fatty acids, fasting glucose, or HOMA-IR were found. Conclusion： Our results indicate that small weight loss does not produce measurable health benefits, whereas short-term regular aerobic exercise can improve glucose and lipid metabolism even in the absence of weight loss in previously sedentary overweight and obese women.