BMJ  2004;329:761 (2 October), doi:10.1136/bmj.329.7469.761-c

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Walking protects elderly people from dementia, studies show

New York

Two American studies published in JAMA show that ordinary, frequent walking protects elderly men and women from dementia and cognitive decline.

One study, of men only ( JAMA 2004;292: 1447[Abstract/Free Full Text]), was an offshoot of the Honolulu heart programme, which began following 8006 men of Japanese ancestry on the Hawaiian island of Oahu in 1965 to 1968 for development of cardiovascular disease. It was designed in a similar way to the Framingham study in Massachusetts.

Regular walking protects elderly people from cognitive decline Credit: KIM STEELE/PHOTONICA

The new study excluded men who had dementia or conditions such as stroke or Parkinson's disease that impaired their ability to walk. From 1991 to 1999 it followed 2257 retired men aged 71 to 93. The cognitive abilities screening instrument, a measure of intellectual function, was used to screen the men. As part of the study the participants had comprehensive examinations that took four to six hours. They completed a cognitive abilities test at baseline and at two follow ups, in 1994-6 and 1997-9.

Lead author Dr Robert Abbott, of the University of Virginia Health System, told the BMJ that Oahu was a "perfect laboratory" for this study. The participants lived in a mild climate with little seasonal variation where outdoor activity was always possible and in communities where walking to local shops, restaurants, friends' homes, or facilities was easy. "We focused on what typical walking behaviour was on a typical day. We think it represented lifelong behaviour," Dr Abbott said.

Men who walked the least (less than 0.4 km, or a quarter of a mile a day) had almost twice (1.8 times) the excess risk of dementia than men who walked more than 3.2 km (2 miles) a day.

The second study, from the nurses health study at the Harvard School of Public Health in Boston, showed that women aged over 70 who had high levels of physical activity did better on cognitive performance tests and showed less cognitive decline than women who were less active ( JAMA 2004;292: 1454[Abstract/Free Full Text]). The researchers conducted questionnaires and telephone interviews every two years to test cognition, verbal memory, category fluency, and attention of 18 000 women aged 71 to 81. The nurses health study began in 1978.

"We found a 20% lower risk of cognitive impairment for women in the highest quintile of activity," the authors write. Women who performed the equivalent of walking at an easy pace for at least 1.5 hours a week had better levels of cognitive performance than those who walked less than 40 minutes a week.

Both studies conclude that long term, regular physical activity, including walking, is associated with better cognitive function and less cognitive decline in elderly participants.

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