Sedentary Lifestyle Linked to Smaller Brain Later in Life

Three people running on treadmills at the gymLow levels of physical activity during midlife may result in smaller brains two decades later, according to a new study published in Neurology.

Though the weight and health benefits of physical fitness are well known, an increasing body of evidence links physical activity to sound mental health and intellectual development. Studies have connected physical activity to a reduction in Alzheimer’s and vascular dementia, as well as an improvement in psychiatric symptoms among people who already have Alzheimer’s.

Exercise releases endorphins, which can offer a temporary boost in mood. Research also suggests exercise can have long-lasting effects, potentially protecting against or treating depression and anxiety. Additional studies suggest exercise may improve cognition and memory.

Can a Sedentary Lifestyle Shrink Your Brain?

For the study, researchers looked at a group of 1,094 people enrolled in the Framingham Heart Study. This group had an average age of 40 and no history of dementia or heart disease.

Between 1979 and 1983, participants completed a treadmill exercise test that required them to continue exercising until they reached 85% of their maximum heart rate or reported being too exhausted to continue. Using an equation that relied on time spent on the treadmill, researchers calculated the physical fitness of each participant. They also looked at blood pressure and heart rate early in the treadmill test, because high heart rate or blood pressure can signal poor physical fitness.

About 20 years later, between 1998 and 2001, the participants completed a shortened version of the treadmill test. They also underwent neuropsychological tests and brain magnetic resonance imaging (MRI) scans to assess brain volume. Brain volume is one way to estimate brain aging.

Those who performed poorly on the treadmill test during middle age had lower brain volume 20 years later. One standard deviation lower of physical fitness correlated to an additional year of brain aging.

A slightly larger sample of 1,583 Framingham Heart Study participants, also with an average age of 40, looked at brain aging among those who developed cardiovascular health problems or who took beta blockers to improve heart health during the study. Among those participants, one standard deviation downward in physical fitness correlated with two years of brain aging.

The researchers say these findings suggest low physical fitness—which often signals a sedentary lifestyle—can escalate brain aging. Among those with cardiovascular risk factors, the effect is even more pronounced.

Exercise Recommendations

The U.S. Centers for Disease Control and Prevention (CDC) recommends the following minimum exercise thresholds:

  • Children should get at least 60 minutes of physical activity—the majority of which should be aerobic—each day.
  • Adults, including seniors and pregnant women who are otherwise healthy, should get at least 150 minutes of moderate-intensity aerobic exercise such as walking per week, or 75 minutes of intense aerobic exercise such as running. They should also perform muscle-strengthening activities such as weight-training at least two days per week, and such activities should target all major muscle groups.

The CDC emphasizes that exercise does not have to occur in long bursts, and even 10 minutes at a time can produce health benefits.


  1. Anderson, P. (2016, February 10). Poor midlife fitness linked to smaller brain volume later. Retrieved from
  2. Depression and anxiety: Exercise eases symptoms. (2014, October 10). Retrieved from
  3. Going beyond risk reduction: Physical exercise may be an effective treatment for Alzheimer’s disease and vascular dementia. (2015, July 23). Retrieved from
  4. Physical activity basics. (2015, June 04). Retrieved from
  5. Spartano, N. L., PhD, Himali, J. J., PhD, Beiser, A. S., PhD, Lewis, G. D., MD, DeCarli, C., MD, Vasan, R. S., MD, & Seshadri, S., MD. (2016). Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later. Neurology. doi:10.1212/WNL.0000000000002415
  6. Weir, K. (2011, December). The exercise effect. Retrieved from
  7. Wlassof, V., PhD. (2015, February 4). Can physical exercise improve cognitive abilities? Retrieved from

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  • Leave a Comment
  • frances


    February 15th, 2016 at 10:20 AM

    I’m not sure how many times we have to repeat that exercise truly is the key to a better life and longer life expectancy.

  • Geoff


    February 15th, 2016 at 1:35 PM

    There is absolutely nothing of any kind of benefit that can be gained from being sedentary. So you are tired and you hurt. You know what helps all of that? getting up and getting moving. It might not come easily for you and you may have to schedule that time into your day just like you do the other important things. But the way I see it, I would rather take 30 minutes out of my day to do something that is GOOD for me instead of ding nothing and literally sitting around and waiting for my brain to shrink and shrivel!

  • Tamar


    February 16th, 2016 at 10:32 AM

    The physical feeling that I get when working out, even when I am hurting and tired, it is kind of like I just know that I am doing something that is good for me.’When I smoke or drink, not so much, I just get the opposite feeling.
    So I am trying to do more consciously choosing to do the things that make me feel good, not those that slow me down and make me feel worse.

  • lyle y

    lyle y

    February 16th, 2016 at 2:12 PM

    You could look to nutrition as a factor in this as well, no?

  • Paris


    February 18th, 2016 at 10:45 AM

    So maybe the new game plan for anyone wanting to preserve their mental health and agility is to walk on a treadmill while doing a crossword puzzle! That would help you maintain both!

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