today is Sep 27, 2022

Phys Ed

Working out at different times of the day might have unique benefits for health, an ambitious new study in mice suggests.

Credit... Victor Moriyama for The New York Times

Gretchen Reynolds

Jan. 19, 2022

Morning exercise has very different effects on metabolism than the same workout later in the day, according to an ambitious new animal study of exercise timing. The study, which involved healthy lab mice jogging on tiny treadmills, mapped hundreds of disparities in the numbers and activities of molecules and genes throughout the rodents’ bodies, depending on whether they ran first thing in the morning or deeper in the evening.

Many of these changes related to fat burning and other aspects of the animals’ metabolisms. Over time, such changes could substantially influence their disease risks and well-being. And though the study featured rodents, its findings likely have relevance for any of us who wonder if it is better to work out before work, or if we might get as much — or more — health benefit from after-hours exercise.