- 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 Brain Fit­ness.

The three pil­lars of an enriched envi­ron­ment are men­tal, phys­i­cal, and social stim­u­la­tion. In pio­neer­ing stud­ies in the 1960s, U.C. 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.