Short bouts of anaerobic exercise increase non-esterified fatty acids release in obesity

PURPOSE: It is demonstrated that aerobic exercise plays an important role in weight loss programs for obesity by increasing 24 h metabolic rate. While aerobic exercise can result in health and fitness benefits in obese subjects, also independently of weight loss, not completely clear are the effects of bouts of hard exercise on metabolic outcomes. The aim of this study was to test the hypothesis that short-term aerobic activity with anaerobic bouts might result in a greater improvement in the management of obesity than aerobic activity alone. METHODS: We studied 16 obese subjects (eight men) during a progressive cycloergometric test up to exhaustion, before and after 4 weeks of two different training schedules (6 days/week). Insulin and glycaemia, non-esterified fatty acids (NEFA) and lactic acid were sampled. Group A (eight subjects, four men) performed an aerobic cycle workout; Group B (eight subjects, four men) performed a 25 min aerobic workout followed by 5 min of anaerobic workout. All the subjects maintained their individual eating habits. RESULTS: The post-training test showed a decrease in AUCs NEFA in Group A (p < 0.05) and an increase in Group B (p < 0.05), together with an increase in lactic acid in Group A and a decrease in Group B (p < 0.01). β-cell function (HOMA2-B) revealed a reduction only in Group A (p < 0.05). Group B achieved a greatest reduction in body fat mass than Group A (p < 0.05). CONCLUSIONS: Aerobic plus anaerobic training seem to produce a greater response in lipid metabolism and not significant modifications in glucose indexes; then, in training prescription for obesity, we might suggest at starting weight loss program aerobic with short bouts of anaerobic training to reduce fat mass and subsequently a prolonged aerobic training alone to ameliorate the metabolic profile.