Women who exercise in the morning lose more body fat, while those who exercise in the evening gain more muscle strength, suggests a study reported in Frontiers in Physiology.¹

This study examined the outcomes in terms of health and performance in individuals who exercised at different times of the day; 27 women and 20 men were assigned to morning (0600–0800 hours) and evening (1830–2030 hours) exercise groups for 12 weeks. Muscular strength, endurance (sit-ups/push-ups) and power (squat jumps; bench throws), body composition, systolic/diastolic BP, respiratory exchange ratio, mood status and dietary intake were assessed at baseline and at the end of the study at 12 weeks.

Significant interactions were noted for muscular strength, endurance, power, fat mass and abdominal fat among women. Those who exercised in the morning had greater reduction in their body fat (total and abdominal) and body fat percentage, while women who exercised in the evening had an increase in upper body muscular strength, endurance and power and also improved overall mood.

Among men, significant interactions were found for systolic BP, respiratory exchange ratio and fatigue. The systolic BP, cholesterol levels, percentage of fat burnt improved significantly among those who exercised in the evening. They also recovered from fatigue.

This study demonstrates that while exercise is beneficial, the time of exercise also affects the health and performance outcomes of exercise, which manifest differently between men and women. Exercise at any time of the day is beneficial. However, time of the exercise may further optimize the individual exercise regimen and outcomes.

Reference

1. Arciero PJ, et al. Morning exercise reduces abdominal fat and blood pressure in women; evening exercise increases muscular performance in women and lowers blood pressure in men. Front Physiol. 2022 May 31;13:893783. doi: 10.3389/fphys.2022.893783.