The Happy Hours of Training

Exercise can play with your circadian rhythm, or how your body clock ticks with the sun, in a good way, according to research published in The Journal of Physiology. In the study, early morning workouts moved the body clock to an earlier time.

WTH does that mean? The shift can help you feel more alert and energised in the morning and tapped out when your body actually should fall asleep—a pattern that better aligns with the sunrise and sunset. Considering that light exposure has a central effect on your clock—which can influence your hormones, body temperature and eating habits, all things that might cause issues if they get out of whack—a 7am workout could help keep you on your A-game all day long.

People who exercise before noon might be set up to lose more pounds than those who exercise after 3pm, according to a study published in the International Journal of Obesity. The theory, per the researchers? In the study, the pre-noon group burnt more calories throughout the day, while later exercisers also tended to take in more calories.

Breaking a sweat before lunch often influences the movement decisions you make throughout the rest of the day, says Esser. If you start off being active, then you're more likely to continue moving all day long, and "that's going to have a higher caloric expenditure overall", she explains. Exercise has also been shown to sway you into making healthier food choices, so that pre-lunch workout could support your wellness intentions all day long.

We all have a resting metabolic rate (RMR), or the baseline amount of energy you burn while awake and at rest, and it's a major player in weight changes. Your body actually burns the most calories while at rest during the afternoon and evening, a study published in the journal Current Biology found.

The researchers found that the changes in RMR paralleled changes in core body temperature, and nothing gets your body temp up like a sweaty workout. "If your resting metabolic rate is higher in the afternoon and you add a workout, that work is going to cost energy on top of your resting metabolic rate", says Esser, leading to more calories burnt during your workout (and in total that day).

If you're hoping to get a bigger burn for the same sweaty effort without changing other lifestyle factors, training now could be your move.

Turns out, your body might be better able to control blood sugar levels after an afternoon workout, as suggests a recent study published in the journal Physiological Reports. Researchers determined that compared with morning workouts, pm ones led to enhanced insulin sensitivity—a good thing—in people with metabolic issues such as pre-diabetes.

Improved blood sugar management throughout the day can help prevent long-term health problems like obesity and cardiovascular disease. And a bonus effect in the moment, per the study: Your body should have more energy during this window, potentially allowing you to give (and thus get) a little more out of your effort. Schweet.

If you instinctively throw another plate on your barbell during an afternoon lifting sesh, there's a reason for that: Your body's ability to perform isometric strength exercises—targeting grip strength or large muscle groups like your quads—peaks in the afternoon, according to a 2020 scientific review published in the journal Physiology. Your body temp is warmer in the afternoon, explain the researchers, which could make it easier for your muscles to produce more force.

As you approach 5pm and later, you might even be able to work out for longer, suggests another study in Applied Physiology, Nutrition and Metabolism. You can thank your body's heightened ability to take in oxygen and shoot it to your working muscles for that.

Skimmed version: Regular late afternoon or evening workouts could lead to improved muscular strength and endurance. And who doesn't want that?

You may have heard (or assumed, or, heck, even experienced) that working out at night gets you all revved up and messes with your sleep. But research published in the journal Experimental Physiology found that nighttime workouts don't disrupt your shut-eye any more than working out during other times of the day. In fact, active night owls actually experienced an increase in the non-rapid eye movement sleep stage, the phase when your body repairs and regenerates tissues, which means training around this time could score you a recovery boost.

A few precautions to ensure your late workout doesn't disrupt your sleep: Keep your routine to a moderate intensity—think a 4–6 on an effort scale of 1–10—and wind down at least an hour before your bedtime, per a scientific review published in Sports Medicine.

See? You really can work out whenever you want and reap the rewards. But if you're gunning for a certain goal, whether that's weight loss or weight room gains, your best approach may be timing your workout to your body's prime moments to shine.