Regular exercise has been shown to benefit the body and to raise spirits. A recent study indicates that physical activity may help the mind as well. According to results reported in Archives of Internal Medicine, physical activity may protect older women from cognitive declines such as memory loss and other decreases in mental function.

The mind-exercise connection

Researchers from the University of California measured the cognitive abilities of nearly 6,000 mostly white women recruited from four centers in the United States. At the onset of the study, all of the women were age 65 and older, able to stand up unaided from a chair and climb a flight of stairs. None had cognitive impairment. The researchers administered a standard test of cognitive function to the women at the beginning of the study and again six to eight years later.

The women were also interviewed to determine their level of physical activity. These measures were based on the amount of walking the women did each day - both for exercise and as a part of their day-to-day routine - and on the number of flights of stairs they climbed each day. The researchers also estimated how many calories per week the women had expended over the past year in specific physical and recreational activities.

Activity pays mental dividends

The researchers divided the women into four groups, based on activity level, and assessed how many in each group experienced a decrease in cognitive function. Overall, as physical activity increased, cognitive decline decreased. The women in the highest group (those who walked the most) were more than one-third less likely to suffer cognitive decline than those who walked the least. The outcomes were about the same when the researchers looked at the results based on calories expended per week.

It is not clear how physical activity might work to lower the risk of cognitive decline. And, because exercise also frequently goes hand-in-hand with other healthful behaviors the researchers were not able to rule out the possibility that it was some other behavior, and not exercise, that accounted for the observed benefits.

How much is enough?

On average, the least active women in this study walked a little more than half a mile each week (1,120 meters) while those in the highest group totaled an average of 17 miles a week (28,000 meters). Those who find 17 miles of walking a week challenging can be heartened by the fact that the women in the next highest activity level (about 7½ miles or 12,320 meters per week) derived almost the same benefits as their more active peers. Bear in mind, too, that for the purposes of this study walking included both walking for fitness and movement as part of daily routine.

If improved health isn't sufficient, the prospect of maintaining mental acuity may be just the motivation sedentary individuals need to get moving.