Dr. Ratey provided a brief history of this research area, sparked by wanting a better understanding of the endorphin rush experienced by marathoners. Empirical study then expanded into a variety of other areas in which exercise affects our mood, sleep, behavior, and our brain. He highlighted how exercise is one way to slow the effects of cognitive decline in dementia, and how exercise allows the hippocampus to grow in older adults who are previously sedentary. He also noted that exercise provides boost in executive function in the frontal cortex in brains of children, particularly as it relates to math. He argued that exercise represents stress inoculation for the brain.
One mechanism by which this happens is though increasing the presence of specific neurotransmitters in the brain. Exercise affects many neurotransmitters, according to Dr. Ratey. For example, increased dopamine after exercising affects motivation, focus, confidence, and affective responses. Additionally, the presence of serotonin increases over time with regular exercise. In addition to these well-known neurotransmitters, he highlighted the importance of neurotropins, which he describes as “fertilizer for the brain.” Among other things, neurotrophins help our plasticity and brain function improve. This actually has the reverse effects on our brains from the stressors of depression on the brain.
In summary, Dr. Ratey strongly encourages exercise for multiple reasons, not least of which is brain health. Intensity and duration of exercise or other specific recommendations are seen as less important than simply engaging in exercise. We now have the science to understand what we have long observed, in terms of how people report feeling after exercising. “Exercise is the ultimate way to improve plasticity in the brain,” Dr. Ratey says in this podcast. The brain’s ability to expand its connections, encode information faster, and other outcomes, appears to all be enhanced by exercise.