Exercise and the Circadian Rhythm

We all know that pulling an all nighter certainly messes up the internal clock inside us, our circadian rhythm. Eating between certain hours of the day has also shown to decrease obesity. Exercise has also been linked to influencing our circadian rhythm. Researchers, Christopher Colwell in particular, have focused on the optimal time for exercising and how it affects the circadian rhythm.

Christopher Colwell, a psychiatry professor at UCLA's Brain Research Institute, conducted a study to test the optimal time of exercise and how it affects the circadian rhythm; although this experiment was conducted on mice it also suggests that it affects human circadian rhythms as well. The mice that were tested on were, for the majority, young and healthy; however, a couple of them had malfunctioning circadian rhythms and had pacemakers inserted into their brains, which functions as an artificial internal clock. Some of the mice were allowed to run freely within their cages, while the other mice were given a wheel to run on at a certain time in the day (in this case, during our afternoon). Mice that exercised, despite the time of day, produced more proteins that reached target organs compared to the mice that were sedentary. Dr. Colwell hypothesized that the mice would produce more proteins in the early morning; however, Dr. Colwell found that "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". Based on this experiment it is evident that target cells (such as the liver, heat, neurons, etc.) all function more strongly when the protein products of the internal-clock cells are released midday rather than early morning.

Dr. Daniel Cavanaugh came to our NEUR 300 seminar course to talk about his research in circadian rhythms. Although the two researchers did not study the same influencing factors and tested on different types of organisms, the two researches together show that the circadian rhythm is not and cannot be limited to just one influencing factor (the two organisms used cannot be compared because Dr. Cavanaugh's Drosophilas do not exercise - flying doesn't count). 

The take away message is that if you're ever debating on whether to go to the gym at 6 AM or sleep in, choose the latter.

Reynolds, Gretchen. "Why Afternoon May Be the Best Time to Exercise." Well Why Afternoon May Be the Best Time to Exercise Comments. N.p., 12 Dec. 2012. Web. 15 Oct. 2015.
http://well.blogs.nytimes.com/2012/12/12/why-afternoon-may-be-the-best-time-to-exercise/