Exercise: Good for the Body, Good for the Mind

Older people may reduce their risk of developing dementia by exercising regularly, according to two studies published in the Journal of the American Medical Association (2004;292:1447–53, 1454–61).

Dementia is characterized by broad impairment in mental or cognitive function, including memory, which progresses with age. Small but measurable changes in cognitive function can occur years before dementia is diagnosed and mark the earliest stages of the disease. As it progresses, it often becomes debilitating, making normal day-to-day activities and self-care impossible. People over 65 years old are most at risk for developing dementia. During the next few decades, this age group is expected to be the fastest-growing segment of the US population.

Several studies have found that physical activity might delay the loss of cognitive abilities in older people, suggesting that exercise might reduce the dementia risk. The two current studies examined the role of exercise in preventing cognitive decline and dementia in older men and women.

The first study involved 2,257 men over 70 years old. To be included in the study, participants had to be physically capable and free of any neurological diseases. Physical activity level and capability were identified at the beginning of the study, and cognitive function was evaluated at the beginning of the study and at two follow-up examinations at approximately three-year intervals. Compared with men who walked 2 miles or more per day, the risk of developing dementia was 33% higher in men who walked 1 to 2 miles per day, 75% higher in men who walked 0.25 to 1 mile per day, and 93% higher in men who walked less than 0.25 miles per day. Furthermore, men who walked fast (approximately 2 miles per hour or more) had a lower risk of dementia than men who walked slowly (approximately 1 mile per hour or less).

In the second study, data were collected from 16,466 women over 70 years old who were participating in a larger health study. As part of the larger study, the participants answered questions about their physical activity in questionnaires that were given to them every two years. Cognitive function was assessed by telephone interviews as the participants entered the study and again between 1.4 and 2.2 years later. Women who exercised most were 20% less likely to have cognitive impairment at the initial interview than women who exercised least. Furthermore, the rate of cognitive decline at the follow-up evaluation in women who exercised most was half that of women who exercised least. The researchers calculated that 1.5 hours per week of walking at an easy pace would reduce cognitive decline by an amount that would occur with about 1.5 years of aging.

The results of these studies suggest that exercise can prevent cognitive decline and dementia. They further suggest that, although intense exercise may be more beneficial, even moderate exercise provides some protection. These findings add to the long list of good reasons for people, including the elderly, to exercise.

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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