News Release

New UCI-led study defines best time to exercise to get the most rejuvenating results

Peer-Reviewed Publication

University of California - Irvine

Paolo Sassone-Corsi, UCI School of Medicine

image: UCI School of Medicine researcher Paolo Sassone-Corsi, Ph.D., leads study revealing 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. view more 

Credit: UCI School of Medicine

A new study led by researchers from the University of California, Irvine finds exercising in the morning, rather than at night, may yield better results.

This study, published today in Cell Metabolism, points to daily timing as a critical variable for metabolic benefits from exercise and implications in chronobiology-based exercise therapy for patients with metabolic disorders.

"Using mice, we compared the impact of exercise on the skeletal muscle metabolism at different times of day," said Paolo Sassone-Corsi, PhD, Donald Bren Professor and director of the Center for Epigenetics and Metabolism at UCI's School of Medicine. "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."

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.

Using high-throughput transcriptomic and metabolomic approaches, 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.


This study was supported by the Novo Nordisk Foundation (NNF14OC0011493 and NNF14OC0000041), Swedish Diabetes Foundation (DIA2015-052), Swedish Research Council (2015-00165), the National Institutes of Health, and INSERM (Institut National de la Sante et Recherche Medicale). Other funding was provided in part by DAPRA (D17AP00002), the National Institutes of Health (GM123558), and the Della Martin Foundation.

About the UCI School of Medicine: Each year, the UCI School of Medicine educates more than 400 medical students, as well as 200 doctoral and master's students. More than 600 residents and fellows are trained at UC Irvine Medical Center and affiliated institutions. The School of Medicine offers an MD; a dual MD/PhD medical scientist training program; and PhDs and master's degrees in anatomy and neurobiology, biomedical sciences, genetic counseling, epidemiology, environmental health sciences, pathology, pharmacology, physiology and biophysics, and translational sciences. Medical students also may pursue an MD/MBA, an MD/master's in public health, or an MD/master's degree through one of three mission-based programs: the Health Education to Advance Leaders in Integrative Medicine (HEAL-IM), the Leadership Education to Advance Diversity-African, Black and Caribbean (LEAD-ABC), and the Program in Medical Education for the Latino Community (PRIME-LC). The UCI School of Medicine is accredited by the Liaison Committee on Medical Accreditation and ranks among the top 50 nationwide for research. For more information, visit

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