Want to help your brain? Work your body. A study published in an online issue of the journal Neurology found that people age 65 and older who walk regularly and got other forms of exercise appear to significantly lower their risk of developing vascular dementia, the second most common form of dementia after Alzheimer’s.

In the four-year study of 749 men and women, researchers measured the amount of energy exerted in the participants’ weekly physical activities, including walking, climbing stairs and other moderate activities, such as house and yard work, gardening, and light carpentry. By the end of the study, 54 people developed Alzheimer’s disease and 27 developed vascular dementia.

The study found the top one-third of participants who exerted the most energy walking were 27 percent less likely to develop vascular dementia than those people in the bottom one-third. It found no association between physical exertion and Alzheimer’s risk.

The researchers can’t say why exercise reduced vascular dementia risk, but say it’s possible that physical activity may improve cerebral blood flow and lower the risk of cerebrovascular disease, which is a risk factor for vascular dementia. But further research is needed about the mechanisms operating between physical activity and memory.