This study followed 2,288 Group Health members age 65 and older for six years. At the start, none showed any signs of dementia or Alzheimer's disease. The researchers contacted the participants every two years, assessing physical and mental functioning. By six years, 319 participants had developed dementia, including 221 with Alzheimer's disease. The participants whose physical function was higher at the start of the study were three times less likely to develop dementia than were those whose physical function was lower.
"Everyone had expected the earliest signs of dementia would be subtle cognitive changes," said Eric B. Larson, MD, MPH, director of Group Health Center for Health Studies. "We were surprised to find that physical changes can precede declines in thinking." What is considered a brain disease may be intimately connected to physical fitness, he added.
In the study, the first indicators of future dementia appeared to be problems with walking and balance. A weak handgrip may be a later sign of the development of dementia in older people.
The National Institute on Aging supported this study. Coauthors are Li Wang, MS, of the Veterans Affairs Puget Sound Health Care System; and James D. Bowen, MD, and Gerald van Belle, PhD, of the University of Washington.
In a recent report, in the Annals of Internal Medicine in January 2006, some of these researchers found that when people exercised regularly, they were less likely to develop dementia, including Alzheimer's disease. The cause of this association was not clear, though. This newer study suggests a possible pathway: that regular exercise may help stave off dementia by improving and maintaining physical conditioning.
"These results suggest that in aging, there's a close link between the mind and body," said Larson. "Physical and mental performance may go hand in hand, and anything you can do to improve one is likely to improve the other." If people notice that they are starting to decline physically, he said, reengaging in physical activity may help them to stop or slow this decline--and reduce their risk of early cognitive worsening.
On the other hand, he said, it is still possible for people who have physical constraints, even paralysis, to stay mentally alert and cognitively fit. Other studies have suggested that staying busy with nonphysical leisure activities and learning new things may also help delay the onset of dementia. Also, "healthy body, healthy mind" is probably only part of the story, he added: Other elements likely include social support and positive mood.
About Group Health Center for Health Studies
Founded in 1947, Group Health is a consumer-governed, nonprofit health care system that coordinates care and coverage. Based in Seattle, Group Health and its subsidiary health carriers, Group Health Options, Inc. and KPS Health Plans, serve more than 574,000 members in Washington and Idaho. Group Health's commercial and Medicare plans have received the top rating of "Excellent" from the National Committee for Quality Assurance (NCQA). Group Health encompasses medical and specialty centers, hospitals (including a full service community hospital), a nationally recognized research center, and a charitable foundation. Group Health and Group Health Permanente (its multispecialty medical group practice) combined employ more than 9,000 staff.
Group Health Center for Health Studies conducts research related to prevention, diagnosis, and treatment of major health problems. It is funded primarily through government and private research grants.
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