Exercise - Possible Protective Factors: Alzheimers

Content provided by the Faculty of the Harvard Medical School

Exercise

Exercise offers an impressive array of health benefits. It helps prevent heart disease and type 2 diabetes; lowers the risk for high blood pressure, colon cancer, and breast cancer; and helps relieve insomnia, anxiety, and depression. But that's not all. Several studies suggest that exercise might also help ward off Alzheimer's disease and other forms of dementia.

One study of 2,000 people, published in 2005 in Lancet Neurology, found that those who exercised during midlife for 20 to 30 minutes twice a week were at least 50% less likely to develop Alzheimer's disease or another dementia in the following decades than people who were sedentary. Earlier, a Canadian study involving 9,000 people over age 65 found that regular exercise cut the risk for cognitive impairment by 37%. Studies of seniors in the United States and the Netherlands have yielded similar results.

Just how exercise may prevent Alzheimer's disease is unclear, but research on mice offers a clue. A 2005 study in the Journal of Neuroscience reported that mice that used their treadmills most often not only proved better able to learn how to get around test mazes than others, but also had fewer deposits of beta-amyloid in their brains. And in the environmental enrichment study described previously, the lowest levels of beta-amyloid and amyloid deposits were found in the most active mice, who spent the most time running and climbing on the toys placed in their cages.

Last updated:	January 23, 2007