Uh oh. Mysore, we have a problem.
According to a new study — details here, but more understandably here at the New York Times — exercise can have profound, beneficial effects on the “body clock,” aka our circadian rhythms, and that effect may be most pronounced when the exercise happens in the afternoon.
So much for early morning Ashtanga. Maybe. (Hold that thought.)
The study comes out of UCLA’s Brain Research Institute. It was performed on mice (some were bred to have malfunctioning internal clocks; I leave any upset about that up to you). I’ll let the NY Times take over from here:
They began by letting healthy mice run, an activity the animals enjoy. Some of the mice ran whenever they wanted. Others were given access to running wheels only in the early portion of their waking time (mice are active at night) or in the later stages, the equivalent of the afternoon for us.
After several weeks of running, the exercising mice, no matter when they ran, were found to be producing more proteins in their internal-clock cells than the sedentary animals. But the difference was slight in these healthy animals, which all had normal circadian rhythms to start with.
So the scientists turned to mice unable to produce a critical internal clock protein. Signals from these animals’ internal clocks rarely reach the rest of the body.
But after several weeks of running, the animals’ internal clocks were sturdier. Messages now traveled to these animals’ hearts and livers far more frequently than in their sedentary counterparts.
The beneficial effect was especially pronounced in those animals that exercised in the afternoon (or mouse equivalent).
That finding, Dr. Colwell says, “was a pretty big surprise.” He and his colleagues had expected to see the greatest effects from morning exercise, a popular workout time for many athletes.
But the animals that ran later produced more clock proteins and pumped the protein more efficiently to the rest of the body than animals that ran early in their day.
The bottom line, albeit an early one? That exercise helps to regulate our body clocks, the researchers say, especially as we hit middle age. And that’s important because an out-of-whack clock has more detrimental effects than just causing you to doze your way through school or work. According to the Times article, recent research shows a link between a messed-up clock and “an increased risk for diabetes, obesity, certain types of cancer, memory loss and mood disorders, including depression.” Yuck.
But what about that focus on the afternoon? Here’s the good news caveat for all you 6 a.m. Mysore types:
What all of this means for people isn’t clear, Dr. Colwell says. “It is evident that exercise will help to regulate” our bodily clocks and circadian rhythms, he says, especially as we enter middle age.
But whether we should opt for an afternoon jog over one in the morning “is impossible to say yet,” he says.
So keep waking up at 5 a.m. if you want. Or, if you’re one of those hardcore “I prefer practicing in the afternoon” people, I’ve just given you more ammo for your battles with the Ashtanga fundamentalists.
Posted by Steve