- Laura asks, “How important is body fitness to mind fitness? And which causes which: body fitness increases mind fitness, or mind fitness increases body fitness?”
- Rachel: “Have you looked much into how more traditional physical exercise can lead to better mental health?”
Dr. Gamon responds:
Very good questions. For years, there has been a large and growing body of evidence that what scientists call an “enriched environment” is crucial for brain health and fitness.
The three pillars of an enriched environment are mental, physical, and social stimulation. In pioneering studies in the 1960s, UC Berkeley researchers such as Marian Diamond showed that rats that get regular exercise literally grow bigger brains than sedentary rats.
A lot of more recent research has corroborated the importance of physical exercise for brain health in humans. This makes sense. After all, the brain is part of the physical body. It is made of cells that are nourished through your blood. So cardiovascular health is obviously important for brain health. Both physical and mental exercise also boost levels of brain-protective chemicals such as growth hormones.
Physical exercise also lowers stress, which can be very harmful to both brain and body. Cortisol is a brain-toxic stress hormone produced naturally by the body. It reduces the blood-glucose energy supply to the brain, causing mental confusion and short-term memory problems. It also interferes with the proper function of the brain’s neurotransmitters, which are chemicals that convey messages from one brain cell to another. Chronic stress can keep cortisol levels high for long enough to kill brain cells, and may even play a role in the development of Alzheimer’s. Physical exercise, mental stimulation, and social interaction can all serve to help lower cortisol levels.
Very recent studies have shown that physical exercise also boosts the brain’s rate of neurogenesis – the rate at which the brain regenerates brain cells. Mental exercise, meanwhile, increases the rate at which those newly-generated brain cells actually survive and become functionally integrated into existing networks in the brain. That’s a neat illustration of the mutually complementary role of physical and mental exercise. You need both for good brain health.