January 16, 2008
Want to help keep your brain sharp into old age? Then start walking. Seniors who regularly took walks and engaged in other forms of moderate exercise had a lower risk of developing vascular dementia, a form of memory loss tied to poor blood flow in the brain. Vascular dementia is the second most common form of dementia, after Alzheimer's disease, and affects a large segment of the senior population. Poor blood flow may also aggravate the memory loss and symptoms of Alzheimer's disease. The findings appeared in Neurology, a medical journal from the American Academy of Neurology.
The four-year study involved nearly 750 older men and women living in Italy. All were over age 65 and free from memory problems at the start of the study. Researchers assessed how much energy the seniors exerted in a typical week, measuring such moderately strenuous activities as walking, climbing stairs, doing work around the house, gardening and yard work, and light carpentry. By the end of the study, 54 people had developed Alzheimer's disease and 27 had developed vascular dementia.
The researchers also assessed overall physical health and medical conditions, as well as genetic factors and socioeconomic factors that indicate increased risk for Alzheimer's and other forms of dementia. After accounting for these factors, the researchers found that those seniors who walked the most, in the top one-third, were 27 percent less likely to develop vascular dementia than those who walked the least. Participants who scored in the top one-third for the most energy exerted in moderate physical activities lowered their risk of vascular dementia by 29 percent, and people who scored in the top one-third for total physical activity lowered their risk by 24 percent compared to those in the bottom one-third.
"Our findings show moderate physical activity, such as walking and other physical activities are associated with a lowered risk of vascular dementia in the elderly independent of several sociodemographic, genetic and medical factors," said study author Dr. Giovanni Ravaglia of University Hospital S. Orsola Malpighi in Bologna, Italy. "It's important to note that an easy-to-perform moderate activity like walking provided the same cognitive benefits as other, more demanding activities."
The researchers note that it's possible that physical activity may improve brain function in various ways. Exercise may help to improve blood vessel health and lower the risk of blood vessel disease, which is a risk factor for dementia. Improved blood flow to the brain may deliver more oxygen and nutrients critical for a clear mind and memory.
Physical activity may also stimulate the growth of brain cells and help to build cognitive reserve, which is believed to protect against symptoms of Alzheimer's. Exercise also lowers stress and levels of stress hormones like cortisol that may damage the brain under some conditions. And finally, an active lifestyle may mean more social interaction and stimulation, which has also been linked to lowered risk of Alzheimer's. Additional research is needed to better understand the mechanisms between physical activity and a robust brain.
Although the current study did not investigate whether there is a link between physical activity and prevention of Alzheimer's disease, other larger studies have. A study from 2004 of more than 2,200 older men living in Hawaii, for example, found that those who walked the least, less than a quarter mile a day, had nearly twice the risk for developing Alzheimer's and other forms of dementia than men who walked more than two miles a day. That same year, the even larger Nurses' Health Study from Harvard reported that women in their 70s who engaged in regular physical activity like walking did better on memory tests than women who were less active. It is also possible that many of the "walkers" are healthier to begin with. So it's difficult to accurately predict the benefit walking has for Alzheimer's prevention.
All these reports, however, add to a growing body of evidence that even modest activities like walking may help keep the brain young. Walking is a relatively easy and popular activity that can be done almost anywhere. Other studies show that it helps to keep weight and blood pressure down and may boost mood as well. Researchers believe that regular exercise improves blood vessel health and blood flow throughout the body, including the brain, and may have additional benefits for heart and brain health.
For more on the benefits of exercise and walking and the prevention of Alzheimer's disease, visit www.ALZinfo.org, The Alzheimer's Information Site.
G. Ravaglia, MD; P. Forti, MD; A. Lucicesare, MD: et al: "Physical Activity and Dementia Risk in the Elderly." Neurology, December 18, 2007.