January 17, 2006

Exercise linked to later onset of dementia

Seattle—Regular exercise is associated with a delay in the onset of dementia and Alzheimer's disease, according to a Group Health Cooperative/University of Washington study that appeared in the Jan. 17 issue of Annals of Internal Medicine.

The study—the most definitive investigation of exercise and dementia to date—also found that the more frail a person is, the more he or she may benefit from exercise.

"Even those elderly people who did modest amounts of gentle exercise, such as walking for 15 minutes three times a week, appeared to benefit," says Eric B. Larson, director of Group Health Center for Health Studies and the lead investigator for the study.

"Based on these findings, we can advise older people to 'use it even after you start to lose it,' because exercise may slow the progression of age-related problems in thinking," said Larson.

The study followed 1,740 Group Health members, aged 65 and older, over a six-year period. The researchers contacted the participants every two years to assess factors potentially affecting dementia, including exercise frequency, cognitive function, physical function, symptoms of depression, and lifestyle characteristics. After six years, 158 participants had developed dementia and 107 of those with dementia had been diagnosed with Alzheimer's disease. People who exercised three or more times a week had a 30 percent to 40 percent lower risk for developing dementia compared with those who exercised fewer than three times per week.

Larson's study was designed to be more definitive than previous research into exercise and dementia—the results of which have been mixed. In this study, Larson's team used test scores to ensure that all participants had a minimum level of function at the time the study began. Doing so eliminated participants who might already be developing Alzheimer's disease, but not showing overt signs of the disease—a factor that would make it difficult to determine the true effects of exercise over the duration of the study.

Larson believes that exercise may improve brain function by boosting blood flow to areas of the brain used for memory. "Earlier research has shown that poor blood flow can damage these parts of the brain," he explained. "So one theory is that exercise may prevent damage and might even help repair these areas by increasing blood flow."

Larson advises older people that it's never too late to begin exercising. "Even if you're 75 and have never exercised before, you can still benefit by starting to exercise now."

Simply walking or swimming for 15 minutes three times a week may be enough, added Larson. And programs such as the "EnhanceFitness" classes that Group Health offers to its Medicare Advantage members can be especially helpful because they are designed with attention to senior safety issues, such as avoiding falls.

"As our population ages, strategies are needed to reduce the risks and delay the onset of dementing disorders such as Alzheimer's disease," Larson said. "These findings indicate that programs that encourage elderly people to exercise should be part of those strategies."

The National Institute of Aging funded the study. Other researchers contributing to the study were the University of Washington's Li Wang, MS; James D. Bowen, MD; Wayne C. McCormick, MD, MPH; Linda Teri, PhD; Paul Crane, MD, MPH; and Walter Kukull, PhD.

About Kaiser Permanente Washington Health Research Institute

Kaiser Permanente Washington Health Research Institute (KPWHRI), formerly Group Health Research Institute, improves the health and health care of Kaiser Permanente members and the public. The Institute has conducted nonproprietary public-interest research on preventing, diagnosing, and treating major health problems since 1983. Government and private research grants provide our main funding. Follow KPWHRI research on Twitter, Facebook, Pinterest, LinkedIn, or YouTube. For more information, go to: www.kpwashingtonresearch.org.

About Kaiser Permanente 

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 11.3 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists, and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery, and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education, and the support of community health. For more information, go to: kp.org/share.


Media contact

For more on Kaiser Permanente Washington Health Research Institute news, please contact:

Rebecca Hughes

hughes.r@ghc.org

206-287-2055
After-hours media line: 206-448-4056

page-twitter-icon.png @KPWaResearch