According to science, this is the best time of day to workout

Health systems recommend adults try and receive at least 60 minutes of moderate-intensity aerobic activity a day. The data is much slimmer on the times of day that yield the most profound effects, however.

The data that is available is conflicting. In two new studies, compelling cases are made in favor of both morning and night as optimal windows for a workout. Both papers were published in the journal, Cell Metabolism. 

The first study uncovered increased production of compounds important to skeletal health in participants who exercised in the evening.

“Physical performance relies on the concerted action of myriad responses, many of which are under circadian clock control. Little is known, however, regarding the time-dependent effect on exercise performance at the molecular level. We found that both mice and humans exhibit daytime variance in exercise capacity between the early and late part of their active phase,” the authors wrote. 

“The distinct daytime and exercise-type transcriptomic and metabolic signature in skeletal muscle point toward a difference in nutrient utilization and metabolic pathway activation, in particular, fatty acid oxidation and glycolysis.”

The second study, much like the first, employed both human and mouse models for analysis.

However, the authors of this report determined that the human body is better at making sense of carbohydrates after a late morning workout session. The researchers also found that we break down fats and amino acids better during this time frame.

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

“We were expecting exercise, just like other forms of modification of our physiology, would be more beneficial, or have a stronger impact, at different times of day and night,” Paolo Sassone-Corsi, PhD, director of the Center for Epigenetics and Metabolism at the University of California Irvine and senior author of the paper, explained. “We just didn’t know when, and the simple fact that we did this demonstrates that the clock itself is rewired, or reprogrammed, by exercise in different ways — whether you do that during the day or during the night. We were expecting it, but this has never been done before.”

The broader analysis seems to support a flexible appreciation of the data above. Perhaps because much of its import is circumstantial.

Setting unique chrontotypes aside, some populations evidence more focus in the morning than they do late in the day while others experience the inverse. Recent studies have suggested that the effectiveness of a workout, as far as physical health is concerned, is largely dependent on a wide range of factors. 

“Do what works for your schedule and choose whatever time makes exercise less of a chore for you. The end goal here is that you can stick to doing this for a long time. So whether that’s crossing exercise off the to-do list first thing in the morning, or giving yourself some time to ease yourself into the mindset, everyone has their preference,” health and fitness expert, Nicole Nam reports, “I will say if you’re more likely to dip on a workout, then just get it out of the way in the morning, but if you’re really looking to put in that work or let off some steam, then wait until your body is already fueled and warmed up from the day.”