Your Brain on Exercise
Exercise Improves Mental Health
It is likely common knowledge by now that physical exercise is good for overall health and emotional well-being, however I think it’s worth taking a slightly deeper dive into this subject, as I find that more in depth knowledge can help people to feel motivated to create new habits. Hundreds of research studies have demonstrated that the benefits of regular exercise go far beyond physical health. Positive effects have been shown for anxiety, depression, bipolar disorder, ADHD, psychotic symptoms, suicidal ideation, insomnia, and cognitive aging.
For example, individuals with major depressive disorder who exercise regularly may need about half the dose of antidepressants compared to those who do not exercise; for me, this evidence creates a powerful argument for psychiatrists to “prescribe” physical exercise to augment medications in patients with depression. Physical exercise can also improve attention and executive functioning in children with ADHD, reduce anxiety in individuals with anxiety disorders, improve symptoms of psychosis in adults with psychotic disorders, and reduce the risk of developing suicidal ideation.
In non-clinical populations (individuals who do not have a mental health diagnosis), exercise can reduce symptoms of anxiety and depression as well.
How Does it Work?
We don’t know with 100% certainty exactly why exercise improves mental health, but we have a pretty good idea of at least a few likely mechanisms in the brain. We know that when people exercise, it leads to an increase in molecules in the brain that reduce neuroinflammation, protect neurons from dying, and promote and stabilize new connections between neurons in areas of the brain that are important for regulating mood and learning. These molecules include irisin (released by skeletal muscles during exercise), BDNF (brain derived neurotrophic factor), the same molecule that scientists believe is responsible for the effects of some antidepressants, and dopamine, a neurotransmitter responsible for motivation, learning and memory, regulating attention, and reinforcing pleasure-seeking behaviors.
I can think of very few down sides to exercise, other than mild and temporary muscle soreness, provided you are exercising in a responsible way, with guidance when needed. The way I like to describe this to my patients who may not feel motivated to exercise, is that it is kind of like taking a medication, but without the side effects. And yes, I do “prescribe” exercise to my patients!
How Much Exercise is Enough?
There are a range of ideas about this, and the answer really depends on the specific research study that is being quoted. In general, following physical activity guidelines from the American Heart Association and U.S. Department of Health and Human Services is a good starting place: 150 minutes of moderate intensity aerobic exercise, or 75 minutes of vigorous aerobic activity per week for adults, and 60 minutes of moderate to vigorous physical activity per day for children and teens.
How Will you Know if it is Working?
I would suggest identifying the specific changes you want to see in your mood and/or symptoms, and keeping track of these over time. Some people start to notice benefits within 3 weeks, and most notice improvements in their target symptoms within 12 weeks.
