“You’re getting cranky. You need to go for a run!!” my wife, Cindy, would say to me. For decades we both intuitively knew what neuroscience research now empirically supports: exercise is not only good for your body, it also helps to regulate your mood and improve your learning and memory. In fact, Harvard brain researcher and author of Spark, Dr. John Ratey, writes, “Going for a run is like taking a little bit of Prozac and a little bit of Ritalin because, like drugs, exercise elevates the neurotransmitters…and balances them.”

So what, specifically, does exercise do to your brain? In a nutshell, exercise affects your neurochemistry by naturally raising and balancing three vital neurotransmitters in your brain, and stimulates the release of neurotrophins like brain-derived neurotrophic factor (BDNF) and insulin-like growth factor (IGF-1). To unpack what all of that means, we need to first back up and review some basics of neuroscience.

Your brain is not a solid mass inside of your skull but consists of billions of interconnected brain cells (neurons), containing microscopic gaps (synapses) between them. The neurons signal one another via neurotransmitters that travel the synaptic gaps between the neurons. How these neurons connect and communicate with one another is determined largely by each individual’s experience and intentional learning. When I was in graduate school in the late 1970s at Johns Hopkins University we were taught that the brain is quite stagnant, meaning that we are born with only so many brain cells and that they die throughout the lifespan. In addition, the dogma at the time was that once groups of neurons were recruited for a specific brain function, they could not be recruited for other functions. However, more recent neuroscience research has proven that the brain is both dynamic and regenerative. The concept of neuroplasticity explains how the activity and structure of the brain is determined by our experiences and the ways in which we use our minds. Furthermore, the neurons that die are replaced by the growth of new brain cells.

Let’s get back to the fascinating ways in which exercise changes the brain. (For more information about neuroplasticity and how our experiences other than exercise change the brain, check out the book The Brain that Changes Itself, by Norman Doidge.) Exercise raises and balances the same three neurotransmitters that are targeted by most of the medications in the mental health field: Norepinephrine, which increases mental alertness and concentration, and promotes stress resilience; Serotonin, which decreases anxiety and elevates mood, impulse control, and motivation; and Dopamine, which increases pleasure, motivation, and attention. Also, exercise releases BDNF and IGF-1, which build and maintain the brain’s cell circuitry. BDNF is sometimes referred to as “Miracle Grow for the brain,” because it increases the number of neurons and the complexity of their connections. Exercise increases both BDNF and IGF-1 in the hippocampus region of your brain, which is responsible for learning and memory. Exercise also increases the amount of blood flow and gray matter in the prefrontal cortex which is responsible for the executive functions found lacking in people with ADHD.

The benefits of exercise are so profound that many mental health providers are prescribing it along with medication and psychotherapy for patients with anxiety, depression, or ADHD. But how much and what type of exercise is the right amount? Although the research is not advanced enough to prescribe an ideal exercise plan, the best approach for building your brain is a combination of aerobic and complex activity that involves some type of skill acquisition, which increases the BDNF in the cerebellum. While aerobic exercise stresses the cardiovascular system and increases the blood flow and oxygen to the brain, skill-based exercise (e.g., rock climbing, yoga, balance drills) utilizes that material to strengthen and expand neural networks.

Although exercise is good brain food, consult with your doctor to make sure you are healthy enough to exercise, and never consider it to be a substitute for your medication.

Jeffrey L. Santee, Ph.D., is a clinical psychologist with advanced training in cognitive psychology and behavioral medicine. In addition to his work in men’s and marital issues, he specializes in the treatment of depression, anxiety disorders, and stress-related health problems. Treatment modalities include individual, marital, and group therapy.