Acute Effect of Morning and Afternoon Aerobic Exercise on Appetite of Overweight Women

The best time of exercise along the day for weight management in overweight and obese patients is not determined. The time of exercise may influence its effect on appetite and food intake. The aim of this study was to compare the effects of two different times of exercise during the day on appetite, energy intake, and the rating of perceived exertion (RPE) on overweight women. Fifty overweight female subjects were recruited in this interventional study. Two sessions of exercise were performed in the morning and afternoon with the target heart rate corresponding to the ventilatory threshold (VT). The appetite was evaluated with visual analogue scale, the energy intake was measured with 24 hours food record and the RPE was determined by visual Borg scale; these variables were compared between the two sessions. The behavior of appetite in relation to hunger, satiety, fullness, prospective food consumption, tendency to salty, savoury, sweet and fatty foods, did not change significantly after both exercise sessions (P > 0.05). Except for the satiety, no significant difference was found among changes in the appetite scores between the two exercise sessions. The median change in the satiety score of the morning exercise was significantly higher than that of the afternoon exercise (5.5 (-8.5, 22.5) vs. -1 (-8, 4.5) respectively, P = 0.01). The median RPE value did not differ significantly between the morning and afternoon sessions (13 (12, 14) vs. 13 (12, 13) respectively, P = 0.46). There was no significant association between the time of exercise and the estimates of the carbohydrate (P = 0.41), fat (P = 0.23), protein (P = 0.13), and calorie intake (P = 0.18). One session of moderate intensity exercise disregarding the time of exercise did not affect appetite significantly. However, morning exercise may cause greater levels of satiety in comparison with afternoon exercise. Moderate intensity aerobic exercise did not alter the patterns of energy intake 24 hours following morning or afternoon exercise.