Physical Fitness and Brain Fitness

- 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.


  1. Senia on September 11, 2006 at 12:17

    …rats that get reg­u­lar exer­cise lit­er­al­ly grow big­ger brains than seden­tary rats.” That is so interesting!

    But do big­ger bri­ans mean bet­ter brains? Thanks.

  2. Dr. Simon Evans on December 8, 2006 at 6:42

    Great arti­cle sum­ma­riz­ing the sym­bio­sis between phys­i­cal and men­tal exer­cis­es to opti­mize brain func­tion. I have to expand on one thing though. 

    Cor­ti­sol get a bad rap on a reg­u­lar basis and it real­ly does­n’t deserve it. Cor­ti­sol is released by the adren­al glands as part of a ‘planned’ response to stres­sors. It has the role of divert­ing ener­gy to sys­tems need­ed to deal with the stress — like chan­nel­ing ener­gy away from high­er brain func­tion and toward mus­cles when escap­ing from a lion. It is a good thing for deal­ing with imme­di­ate and short term stress. It gets prob­lem­at­ic for the brain when long peri­ods of stress keep the sys­tam active. 

    It is impor­tant for peo­ple to under­stand that cor­ti­sol can be a ‘good guy’ because new drugs are appear­ing in the weight loss indus­try that block cor­ti­sol. Mess­ing with the func­tion of this incred­i­bly pow­er­ful hor­mone is a recipe for disaster.

  3. Caroline on December 14, 2006 at 5:27

    Simon — great point. The key to remem­ber with stress and stress hor­mones, like most every­thing else, is mod­er­a­tion. While some stress (the short-lived type) can be help­ful or even life-sav­ing, chron­ic stress with­out any relief tends to gnaw away at you.

    Read Is there such thing as GOOD stress? for more dis­cus­sion on acute vs. chron­ic stress.

    I also agree that arti­fi­cial­ly alter­ing your body’s chem­istry has the clear poten­tial for trouble.

About SharpBrains

SHARPBRAINS is an independent think-tank and consulting firm providing services at the frontier of applied neuroscience, health, leadership and innovation.
SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

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