In that a number of previous studies have demonstrated an inverse relationship between physical activity and cognitive decline as well as a risk of dementia, Zaldy S. Tan, from Harvard Medical School (Massachusetts, USA), and colleagues examined the extent of exercise as a factor in lowering the risk of dementia.   Reviewing data from 1,211 participants in the Framingham Heart Study, the team found that those subjects who reported moderate to heavy physical activity were at 45% lower risk of all-cause dementia, as compared with light exercisers.  Additionally, moderate exercise appeared to be protective.  Writing that: “Moderate to heavy physical activity is associated with a reduced risk for dementia, for up to two decades of follow-up,” the team urges that: “Our data emphasize that a reduced risk of dementia may be one additional health benefit to adults of maintaining at least moderate physical activity.”