Comparison between the effect of 6 weeks of morning or evening aerobic exercise on appetite and anthropometric indices: a randomized controlled trial

Several studies have shown that exercise is directly related to creating negative energy balance and changes in appetite. However, few studies have examined the effect of exercise time during the day on these factors. The aim of the present study was to demonstrate the effect of 6 weeks of morning and evening aerobic exercise on appetite and anthropometric indices. A total of 48 overweight females were recruited to this clinical trial. By the time of exercise, they were divided into two groups (morning or evening) and performed 6 weeks of exercise with a target heart rate on the ventilatory threshold. Appetite change, calorie intake and anthropometric indices were assessed. Consistent changes in appetite scores were not found during the 6 weeks (P > 0.05). Calorie consumption of the morning group decreased significantly more than that of the evening group (P = 0.02) during the 6 weeks. In addition, significant changes in body weight, body mass index, abdominal skin fold thickness and abdominal circumference were seen in the morning group. It appears that moderate- to high-intensity aerobic exercise in the morning could be considered a more effective programme than evening exercise on appetite control, calorie intake and weight loss in inactive overweight women. However, the limitations of the study, such as short-term duration, should be noticed.