One Major Side Effect of Working Out in the Morning, Says Study

Kiersten Hickman
·3-min read
arms up squat

Does the early bird really get the worm? Or is a post-work sweat sesh the way to go? While working out at any time of the day is good for your physical and mental health, one study published by the University of Copenhagen states that exercising in the morning will "result in an increased metabolic response in skeletal muscle." In simpler terms, morning exercise can give your metabolism a boost when trying to digest sugar and fat throughout the day.

Here's why, and for even more healthy tips, be sure to check out our list of 15 Underrated Weight Loss Tips That Actually Work.

Why working out in the morning boosts your metabolism.

The science behind this theory is specific to the body's circadian clock. According to the Center for Disease Control and Prevention (CDC), a circadian clock is the driven cycle within your body that will "rise and fall" during a 24-hour day. It's how your body responds to the sun's light and dark cycle throughout the day. Your hormonal activity, body temperature, eating and sleeping schedules all are linked to this cycle. It's also closely correlated to your melatonin levels, which helps your body to relax and fall into a deep sleep, and wake up in the morning when you're feeling refreshed.

So how are these correlated? In the study, researchers used mice to determine the effect of exercise at different times of the day. As it turns out, the mice that worked out in the morning (at the beginning of the active phase, when your brain is most sharp) resulted in a higher metabolic response throughout the day, compared to working out at the beginning of the "resting phase" of your day, which starts in the evening. That's because morning exercise can initiate gene programs in your muscle cells, creating an even more effective metabolizing structure for your body.

Is it bad to exercise at night?

Of course not! Again, it's important to move your body and to pick a time that works well for your schedule. The published study clearly states that exercise in the evening does still increase energy expenditure hours after the exercise session, meaning you will still burn calories and get your metabolism going.

The research simply shows by getting your body moving during your active part of the day (when the sun is up and your body is geared to get things done), your metabolism and muscle cells respond to that kind of energy, causing a faster metabolic response.

"On this basis we cannot say for certain which is best, exercise in the morning or exercise in the evening," says Jonas Thue Treebak, associate professor from the Novo Nordisk Foundation Center for Basic Metabolic Research, when interviewed for the study. "At this point, we can only conclude that the effects of the two appear to differ, and we certainly have to do more work to determine the potential mechanisms for the beneficial effects of exercise training performed at these two time-points."

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