What’s the Best Time of Day to Exercise?

Some people like to "start off the day on the right foot" with a workout, while others feel that they need to "get the engine running first" and prefer to exercise at night. When some people exercise at night, they can't get to sleep, while others say that exercise acts as a sedative.

New research, indicates that our biological clock "likes" daytime workouts better. Your circadian rhythms appear to be even synched at the muscle cell level.

Research by scientists at Northwestern University in Chicago, Illinois, revealed that muscles have their own internal clocks and as a result, function better during the day than they do at night. It might seem illogical that your workout could yield different fitness results, depending on the time of day that you workout. Daytime workouts yield more benefit than nighttime workouts.

Joseph Bass, MD, is the senior study author and chief of endocrinology, metabolism and molecular medicine at Northwestern. Dr. Bass stated: “Oxygen and the internal clock are doing a dance together inside muscle cells to produce energy, and the time of day determines how well that dance is synchronized … The capacity for a cell to perform its most important functions, to contract, will vary according to the time of day.”

Your muscles’ ability to use oxygen for energy and to adapt to the demands of exercise, is most efficient during the day, or whatever are the normal waking hours for a given organism. For example, mice are nocturnal, so night time turned out to be the better exercise time for them.

The Best Exercise Time Is...

Any exercise is better than no exercise, but if your schedule allows it, you should, in terms of your circadian rhythm, exercise in the afternoon. The next best time to exercise is the morning, with nighttime exercise coming in last. Nighttime exercise can lead to developing other circadian disruptions, including poor sleep.

Your body temperature also tends to be a degree or two warmer in the afternoon than in the morning, resulting in better muscle performance and a decreased risk of injury.

Exercising in the morning on an empty stomach, is useful for preventing both weight gain and insulin resistance. The combination of fasting and exercising, forces the body to burn fat. If you have trouble exercising on an empty stomach, you can consume 20 grams of a fast-assimilating protein, such as a high-quality whey protein concentrate, about 30 minutes before your workout.

The bottom line here is that everyone might not be built exactly the same. It is best to listen to your body and let your body be your guide in choosing what time of day works best for you.

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