Afternoon Exercise May Be The Best

It turns out that the best time to exercise might be in the afternoon, according to a new study published by the LA Brain Research Institute in the Journal of Physiology. Our bodies have an endogenous circadian rhythm, an internal clock, which controls everything from our hearts to our brains. Sometimes that clock gets out of whack, and researchers say that exercise can help put it back on the right track.

The preliminary results, based on results on mice, suggest that midday is the time when exercise most affects our circadian rhythm in a positive way. We have cells within our brains that help us tell what time of day it is, which influences when we naturally sleep and wake, among other things.

Signals from light and darkness cause genes within these cells to produce proteins and release them into the body. From there, they move to all our vital organs and keep them synchronized.

The problem is, sometimes our internal clocks don’t function like they ought to. They get confused and off because of things like artificial light in the evening; even aging makes the internal clock less functional. When this happens, we have a harder time falling asleep, sleeping through the night, and staying awake during the day. More severe consequences are a higher risk for diabetes, obesity, some types of cancer, memory loss, and mood disorders.

But Dr. Christopher Colwell and his colleagues believe that exercising may be the key to getting our circadian rhythms back to normal. After several weeks of letting healthy mice run on a regular basis, they found that their circadian protein production was up, meaning their internal clocks were being regulated effectively.

Some mice had malfunctioning internal clocks, so the researchers had these mice exercise at different times of the day to see if running would also help “fix” them. As it turned out, these mice also started producing more of the proteins, especially those who ran during the equivalent to our “afternoon.” Their internal clocks were functioning better than they had been before.

What this study tells us is that exercising in the morning and afternoon does help our internal clocks regulate. Colwell says that some evidence he’s gathered suggests that late-night exercise might actually be harmful to our sleep rhythms, though. More research will need to be done before the specifics can be nailed down. But one thing’s (still) for certain: exercise is good for us!