Cognitive Function Improves With Exercise

Abbott RD, White LR, Ross GW, et al. Walking and dementia in physically capable elderly men. JAMA. 2004;292:1447-1453.

Weuve J, Kang JH, Manson JE, et al. Physical activity, including walking, and cognitive function in older women. JAMA. 2004;292:1454-1461.

Walking--and exercise in general--is clearly associated with better cognitive function and a reduced risk of cognitive decline in elderly men and women, according to two recent reports in JAMA.

According to Abbott et al, older men who walked the least in a comparison group were twice as likely to have dementia as men who walked the most. In their study of 2,257 men between ages 71 and 93, the researchers assessed the distance participants walked each day from 1991 to 1993. They then conducted two follow-up assessments between 1994 and 1999, in which they identified 158 cases of dementia.

The investigators found that, compared with men who walked more than two miles per day, those who walked less than a quarter mile per day were 1.8 times more likely to have dementia, and those who walked a quarter mile to one mile per day had a 71% increased risk of dementia. On average, men who walked more were younger, had higher physical performance scores, and were better educated than their less active counterparts.

While offering "no clear explanations for the relation between walking and dementia," the researchers noted that "people who are active tend to adhere to a healthier lifestyle and a better diet than those who are inactive," and they generally enjoy greater vitality and better health. "There is also the possibility that people who walk are less likely to get diseases later in life that could lead to dementia," they suggest.

Meanwhile, beginning in 1986, Weuve and colleagues conducted biennial questionnaires among 18,766 women ages 70 to 81 concerning time spent per week in vigorous activities, including running, jogging, walking or hiking outdoors, participating in racquet sports, swimming laps, bicycling, aerobic dancing, and using exercise machines. The women were also asked about their usual outdoor walking pace. From 1995 to 2001, trained nurses conducted telephone interviews with the participants, testing general cognition, verbal memory, category fluency, and attention.

Results indicated that higher levels of physical exercise were associated with better cognitive performance. Women who engaged in the greatest amount of physical activity had a 20% lower risk of cognitive impairment, compared with women who exercised the least. Furthermore, researchers found higher cognitive scores among women who walked at an easy pace for at least 1.5 hours per week than among those walking less than 40 minutes. The apparent cognitive benefits of exercise, observe Weuve et al, compare with "being about three years younger."