How Exercise is Like Miracle Grow for the Brain
10/27/2024 by Dr. Rachel Dillinger, MD PMH-C, integrative and reproductive psychiatrist
From a healthier heart to a stronger immune system, many people are already well aware of the ways physical exercise can benefit our bodies.
You may notice that it helps your mental health, too. While a boost in endorphins and dopamine (feel good chemicals) and drop in cortisol (a stress related chemical) help accomplish this during and just after exercise, a lesser-known substance released by our brain helps give lasting positive effects: brain-derived neurotrophic factor (BDNF).
Your brain is made up of cells called neurons. Neurons “talk” to each other to send messages throughout your brain and body. They somewhat resemble trees, with the “branches” called dendrites reaching out and connecting with other neurons.
Our brain can grow, break down, and restructure these branches and connections based on our needs and how often they get used. In some conditions like depression, the environment in our brain leads to fewer branches and connections. This can help to explain some of the symptoms people may notice when they have a depressive episode: slower thinking and moving, lower energy and motivation, and feeling like everything takes more effort.
There are a number of things that can help combat this, and many of them stimulate the release of BDNF. BDNF acts like miracle grow for neurons in the brain, causing the dendrites to strengthen, branch, and form new connections much more easily than when it’s not around. It also makes a neuron more likely to survive, prolonging its lifespan and protecting our brain.
Certain medications (selective serotonin reuptake inhibitors like prozac and lexapro, and others like lithium and ketamine) and interventional treatments (TMS and ECT) have been shown to increase BDNF levels. The image below from this study shows growth after 2, 3 and 4 weeks on fluoxetine:
Exercise is another potent option that can lead to increased BDNF levels of 30-40%. The most return on your investment will come from exercises that require periods of more intense effort followed by less intense effort-think high intensity interval training (HIIT) and powerlifting). If that’s not enough to get your moving, consider this: researchers found that for the study control groups who were instructed to be sedentary during the course of the trial, their BDNF levels actually dropped over 10%.
Since exercise primes your neurons to grow and form new connections, you will get a higher return on investment for the efforts you put in around this time to form new habits and thinking patterns through therapy, meditation, journaling and more. If you haven’t included exercise in your treatment plan, now is the perfect time to add it in!