The efficacy of morning versus evening exercise for weight loss: A randomized controlled trial

ObjectiveThe aim of this study was to investigate the influence of morning versus evening exercise on weight loss, cardiometabolic health, and components of energy balance. MethodsA total of 100 inactive adults with overweight or obesity were randomized to morning exercise (AMEx; 06:00-09:00), evening exercise (PMEx; 16:00-19:00), or wait-list control (CON). AMEx and PMEx were prescribed 250 min center dot wk(-1) of self-paced aerobic exercise for 12 weeks. Anthropometry and body composition, physical activity, and dietary intake were assessed at baseline, 6 weeks, and 12 weeks. Cardiorespiratory fitness (V?O(2)peak), resting metabolic rate, and blood markers were assessed at baseline and 12 weeks. Body composition and V?O(2)peak were also measured at 3- and 6-month follow-up. ResultsAMEx and PMEx lost weight during the intervention (mean [SD], AMEx, -2.7 [2.5] kg, p < 0.001; PMEx, -3.1 [3.4] kg, p < 0.001). V?O(2)peak significantly increased in both intervention groups, and these changes were different from CON (AMEx, +4.7 mL center dot kg(-1)center dot min(-1), p = 0.034; PMEx, +4.2 mL center dot kg(-1)center dot min(-1), p = 0.045). There were no between-group differences for resting metabolic rate or physical activity. At 12 weeks, total energy intake was significantly reduced in both AMEx and PMEx versus CON (AMEx, -3974 kJ, p < 0.001; PMEx, -3165 kJ, p = 0.001). ConclusionsAdults with overweight and obesity experience modest weight loss in response to an exercise program, but there does not appear to be an optimal time to exercise.

Automated summary

This study aimed to investigate the influence of morning versus evening exercise on weight loss, cardiometabolic health, and components of energy balance. The results showed that both morning and evening exercise can lead to weight loss, but there does not appear to be an optimal time to exercise.