Mid-morning Best Time to Exercise, Study Finds

A new study finds that mid-morning is the best time to exercise. “We discovered that exercising at the correct time of day – around mid-morning – results in more oxygen in the cells and a more rejuvenating effect on the body,” said University of California-Irvine School of Medicine professor Paolo Sassone-Corsi, PhD.

The study, published today in Cell Metabolism, points to daily timing as a critical variable for metabolic benefits from exercise.

“Using mice, we compared the impact of exercise on the skeletal muscle metabolism at different times of day,” said Sassone-Corsi.

Until now, it was understood that the timing of food intake was important, but it was unclear whether the effects of exercise on energy metabolism were restricted to unique time windows.

“Exercise stimulates metabolism, leading to the improvement of metabolic health. While the metabolic benefits from exercise have been extensively uncovered, the question of when it is appropriate to exercise has remained virtually unexplored,” said Sassone-Corsi.

Metabolism of mice

The research team identified distinct changes in the metabolism of mice that occurred during exercise in either the early rest phase (evening) or the early active phase (morning). The impact of exercise in the morning resulted in higher utilization of carbohydrates and ketone bodies, as well as the breakdown of fats and amino acids.

“Our results clearly indicate that time-of-day is a critical factor to amplify the beneficial impact of exercise on both metabolic pathways within skeletal muscle and systemic energy homeostasis,” said Sassone-Corsi.