How Much Exercise is Needed to Reduce the Risk of Dementia?
Older adults who exercised at least three times a week were much less likely to develop dementia than those who were less active, according to a study reported and funded by the National Institute on Aging (NIA).
Researchers pointed out that this study did not demonstrate directly that exercise reduces risk of dementia, but it joins a growing list of observational research that finds a correlation between exercise and dementia -- also known as cognitive decline -- which is associated with Alzheimer's disease.
How was this Exercise and Dementia Research Conducted?
This dementia study, reported in the January 17, 2006, issue of The Annals of Internal Medicine, was a joint effort of the Group Health Cooperative (GHC), the University of Washington, and the VA Puget Sound Health Care System, all in Seattle, Washington.
- Researchers followed 1,740 GHC members age 65 or older for an average of 6.2 years between 1994 and 2003.
- When the study began, the participants -- all of whom were tested and found to be cognitively normal -- reported the number of days per week they engaged in at least 15 minutes of physical activity, such as walking, hiking, bicycling, aerobics, or weight training.
- The participants’ cognitive function was assessed, and new cases of dementia were identified, every 2 years.
- By the end of the study, the rate of developing dementia was significantly lower for those who exercised more:
- 13.0 per 1,000 "person years" for those who exercised three or more times weekly
- 19.7 per 1,000 "person years" for those who exercised fewer than three times per week
- Researchers determined that people who exercised at least 3 times per week had a 32 percent reduction in risk of developing dementia.
Reduced Risk of Dementia: a New Reason to Exercise
"Physical activity has been shown to be beneficial for health and aging in a number of areas," said Dallas Anderson, Ph.D., program director for population studies in the Dementias of Aging Branch of NIA's Neuroscience and Neuropsychology of Aging Program.
"This emerging association between exercise and cognitive health is increasingly important to understand."
More Research Coming on the Effects of Exercise on Dementia
The NIA also announced its support for clinical trials which will test the direct effects of exercise on cognitive function, or dementia.
Anderson said this research should help sort out whether exercise reduces risk of cognitive decline or whether other factors related to exercise, such as increased social interaction, play a role.
Additional study also may provide information on the possible merits of varying types of exercise.
- For information about Alzheimer's disease, visit the Alzheimer's Disease Education and Referral (ADEAR) Center website, or call the ADEAR Center toll free at 1-800-438-4380. ADEAR is a service of the National Institutes of Health.
- To participate in an Alzheimer’s disease clinical trial, visit the U.S. government clinical trials site and search for Alzheimer's disease trials.
- A free 80-page exercise booklet titled "Exercise: A Guide from the National Institute on Aging", is available in English or Spanish. A companion video is also available.
- To order the booklet and video by phone, call 1-800-222-2225
- You can also order online at the NIA Information Center, or download the booklet directly from the site.
The NIA is part of the National Institutes of Health, a division of the U.S. Department of Health and Human Services.