Expert

Exercise and Brain Health

Tuesday, July 1, 2014

It is widely accepted now that “what is good for the heart is good for the brain.” Physical activity, good nutrition, adequate sleep, stress reduction, and control of risk factors such as high cholesterol and elevated blood pressure protect not only cardiac health but also support optimal brain health.

It is widely accepted now that “what is good for the heart is good for the brain.” Physical activity, good nutrition, adequate sleep, stress reduction, and control of risk factors such as high cholesterol and elevated blood pressure protect not only cardiac health but also support optimal brain health. For physical activity in particular, the evidence strongly supports a connection between regular exercise and improved cognitive aging, greater delay in the onset of Alzheimer’s disease, and better functioning in individuals already affected by cognitive impairment.

Why Exercise is Beneficial

There are many reasons why physical activity might benefit brain health. Exercise helps regulate blood pressure and it lowers the levels of blood fats.  This can favorably affect the risk for arteriosclerotic vascular disease that affects both heart and brain. Exercise helps maintain healthy responsiveness of cells to insulin, a regulator of metabolism. When insulin sensitivity is protected, the development of diabetes may be less likely. Exercise also decreases inflammatory responses throughout the body. We know from recent research that inflammation can increase heart disease and also set the stage for accelerated aging, depression, and major neurocognitive disorders (the newer term that includes what we have called dementia in the past).

Many Forms of Exercise are Important

Many of us think of exercise mostly in terms of aerobic activity such as running, cycling, or swimming. In older adults especially, there are other forms of physical activity that are just as important! Resistance training uses weights, elastic bands, or even the body’s own mass to build muscle strength. Bone health, too, is protected by challenging our muscles with resistance.  Flexibility training or stretching keeps the joints supple and maintains our ability to bend safely. Tying our shoes, picking things up off the ground, or turning to see what is behind our cars when we back up require considerable flexibility. Balance training, finally, reduces risk for one of the major sources of disability and death in older adults: fall-related injuries. Simple, brief exercises can improve gait and stance stability enough to make a real difference in safety, and this is no small benefit when we consider that falls in older adults are made more likely and more dangerous by slower reaction time, more fragile bones, and visual impairment among other age-associated changes.

Among the many randomized, controlled trials that have tested the benefits of exercise for cognitive health, positive findings have been frequent. One comprehensive study of studies, or meta-analysis, included 24 high quality trials of aerobic exercise, or aerobic exercise combined with strength training, in mixed-age adults. Many of these adults were older, some in their 80s, and age in any case seemed unimportant in predicting the observed improvements. Exercise helped the participants of these studies achieve measurable improvements in attention, processing speed, executive function, and aspects of memory1.

Delaying Cognitive Decline

Even after cognitive loss has begun, physical activity may be able to delay further loss. One of the controlled comparisons of physical exercise to placebo in older adults with memory complaints showed that after even 24 weeks of moderate exercise there was significant improvement in measures of cognitive impairment. It was striking, too, that the gains lasted another year and a half after the exercise program had ended.2   Along with the expected improvement in physical fitness and function, physical activity has even been shown to improve behaviors and cognitive function in people already affected by dementia. A recent meta-analysis demonstrated that the size of the cognitive benefit was on a par with the size of other benefits.3

Talk with Your Doctor

In light of the strong support for benefits of physical exercise as a preventive or palliative intervention for cognitive decline, it’s remarkable that health care professionals often fail to advise their patients, especially older patients, how very important activity can be. It was estimated in 2003-2005 that only about 15% or fewer of men and women age 65 and older received exercise counseling from their primary care physicians.4 Since that time, of course, the benefits of exercise have been publicized much more, and perhaps a more current study would show improvement. The amount of exercise recommended for healthy adults over age 65 is relatively modest: aerobic exercise at an appropriate moderate level five days each week for 30 minutes each day, or at a vigorous level for 20 minutes on three days per week, along with resistance training (two to three times per week), flexibility training, and balance exercises as appropriate.5

Summary

The fight against cognitive aging and cognitive decline is advancing on many fronts. Perhaps we will understand more in the near future about early identification of people at risk. We may find more effective symptom-reducing medications and even medicines that prevent or moderate the disease’s course. But even before such advances, physical activity provides a readily available tool for helping to protect our brains, functioning, and even safety. Let’s keep active!

BrightFocus Foundation is a nonprofit organization supporting research and public education to help eradicate brain and eye diseases, including macular degeneration and glaucoma. For more information, call 1-800-437-2423.


Sources

  1. Smith PJ, Blumenthal JA, Hoffman BM, et al. Aerobic exercise and neurocognitive performance: a meta-analytic review of randomized controlled trials. Psychosomatic Medicine 2010;72:239-52.
  2. Lautenschlager NT, Cox KL, Flicker L, et al.  Effect of physical activity on cognitive function in older adults at risk for Alzheimer disease: a randomized trial. JAMA 2008;300:1027-37.
  3. Heyn P, Abreu BC, Ottenbacher KJ. The effects of exercise training on elderly persons with cognitive impairment and dementia: a meta-analysis. Arch Phys Med Rehabil. 2004;85:1694-704.
  4. 2003-2005 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey data files. http://www.cdc.gov/nch
  5. Nelson ME, Rejeski WJ, Blair SN, et al.   Physical activity and public health in older adults: recommendation from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc. 2007;39:1435-45.

 

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