Everyone knows that exercise is good for you and every doctor supports increased exercise. We all know that it is an essential part of a healthy lifestyle and it is readily apparent that when you exercise, you feel good afterwards. I, for one, always feel like I’ve accomplished so much in my day just by taking a 20 minute jog and it makes the rest of my day so much more productive. But, why is exercise so good for you?
Psychiatrists, natural medicine practitioners and people that endorse a holistic approach to health prescribe exercise as a treatment for depression and mood irregularities. They often claim that it can make you feel happier and even stabilize the autonomic nervous system. Many people will agree that they notice these effects on an individual level, however the mechanisms / physiology that mediates this effect has yet to be elucidated.
The New England Journal of Medicine recently released an interesting article about the effects of exercise on mood. I find this article interesting because it proposes a mechanism for how this effect can be explained. The basic gist of the research is that our bodies normally break down tryptophan into various metabolites in our skeletal muscle, liver and white blood cells. These metabolites can then cross into the brain and mediate our response to stress. If too much tryptophan is broken down and too much of its metabolite reaches our brain, we can become more sensitive to stressors. The stress pathway in the brain has been associated with the pathophysiology of several different mental illnesses, especially depression.
The researchers of this study found that by increasing muscle mass by exercising, the body activates a separate pathway that makes the metabolite of tryptophan no longer able to cross the blood brain barrier. This naturally prevents too much from entering the brain, and thus might be an explanation for why exercise seems to help people’s mood and improve depression.
So what’s to lose? Get out there and exercise!