Exercise and the Brain

I have been pushing exercise for 15 years, at least. The evidence for the beneficial effects of exercising keeps accumulating. Exercise helps us to manage stress, lower anxiety, and improve our mood and outlook. Dopamine is released in the brain after exercise that helps people with ADHD to focus. Everyone knows these things, but it doesn’t mean they exercise. Young adults know about the endorphins released in the famous and illusive “runner’s high.” Yet, none have ever experienced it. What they experience is that exercise is really hard. It takes a lot of work and persistence to find the “high” of exercise, and most people who are depressed are the last to find that gear.

Ten years ago with input from the neurosciences I found a new angle to promote exercise. There are stem cells in the hippocampus of the brain. The hippocampus is important in consolidating memory and managing emotions. The stem cells are triggered to make new neurons by physical exercise. These neurons are then mapped into pathways by new learning. Movement, learning, and mood all come together with exercise! We also know that the hippocampus shrinks when a person is depressed or under chronic stress. It seemed to be a great way to encourage the young adults I see with mood disorders to exercise. The parents listened carefully to the advice. Maybe they have gotten moving.

Now I have new research input to share. We now have some indicators for how exercise may benefit the brain. An article by Gretchen Reynolds in the New York Times discusses the research that sheds light on: How Exercise May Protect Against Depression. Scientist in Stockholm bred “pre-exercised mice” that produced high levels of an enzyme, PGC-1alpha1, in their muscles. Even after weeks of mild stress, these mice rich in PGC-1alpha1 seemed to behave normally and were considered depression-resistant compared to controls.

The scientists then studied what happened in the bloodstream of both groups of mice. When animals and humans are stressed they produce kynurenine which passes through the blood-brain barrier and causes inflammation in the brain. This inflammation may be what causes depression. In the pre-exercise mice with high levels of PGC-1alpha1, the kynurenine produced under stress is attacked by a protein promoted by the PGC-1alpha1. The kynurenine is broken into its “component parts, which, interestingly, could not pass the blood-brain barrier.” Similar results were found when the researchers studied muscle biopsies in humans before and after 3 weeks of moderate aerobic exercise. There was a significant increase in PGC-1alpha1 in humans tested after the 3 weeks. Hence, there is a clearer understanding of how exercise may protect the brain, and with that protection, lower the chances of depression.

Young adults may not recognize that inflammation is an important buzzword in medicine these days. The annals of medical journals are filled with articles discussing efforts to reduce inflammation at a cellular level. (I had a homeopathic-type family physician 15 years ago who tried to convey to me the importance of reducing inflammation at a cellular level! Did I listen? Not so much). Now we all need to listen.

I have a running shirt that says, “Running is cheaper than therapy.” I do still want to make a living, but I would like more people, young and old, to make exercise a regular part of their day.

http://well.blogs.nytimes.com/2014l/10/01/how-exercise-may-protect-against-depression/?_php=true&_type=blogs&_r=0