It isn't news that regular physical exercise — the kind that gets your heart rate up and builds up a sweat — is great for your body. Exercise decreases the risk of cardiovascular disease , one of the leading causes of death, it energizes us, and in general makes us feel great. What is less well-known is that exercise has equally profound and positive effects on the brain . 

My own experience of those effects was so powerful, it moved me to shift my neuroscience research from a focus on brain areas critical for long-term memory to a focus on understanding how exercise improves brain function in humans. In the most recent installment of my podcast Totally Cerebral (part of the PRX series Transistor), I tell the story of this personal and scientific shift, as well as pay homage to my scientific mentor, anatomist Marian Diamond.

I can remember the day I first realized I wanted to become a neuroscientist. I was a freshman at U.C. Berkeley taking a course called "The Brain and its Potential," taught by Diamond, one of the most popular teachers at the university. On the first day of class, Diamond told us about the brain's amazing ability to change in response to the environment, called brain plasticity, and her classic experiments that she began in the late 1950s. She examined the changes in the brains of rats raised in what she called "enriched" environments, with lots of toys and lots of other rats to play with. She showed that, when compared to rats raised in an impoverished environment with no toys and just a few other rats around, the rats in enriched environments developed a significantly thicker outer covering of the brain (called the cortex), had increased levels of the neurotransmitter acetylcholine (important for memory), and more synapses, the structure that allows brain cells to communicate with each other.