Staying mentally active doesn’t prevent Alzheimer’s, can delay it. The common wisdom about keeping your brain healthy with age is to keep it busy, but most of those recommendations came from studies looking at brains after death. Now, a team of researchers has looked at living brains to see how these mental gymnastics might help in the living. “The researchers collected data on the current and lifetime physical and mental activity of almost 200 people who didn’t have any memory or thinking problems. Their average age was 74. People in the study had PET and MRI scans so researchers could gauge signs of Alzheimer’s disease. In addition, participants took tests to evaluate their thinking and mental skills. They found that histories of mental activity were related to overall intelligence and generally to performance on tests of mental performance. But, these activities weren’t related to the presence of Alzheimer’s disease markers, such as beta-amyloid deposits in the brain. In fact, although people who kept their brains busy with stimulating mental activities had higher IQs and better mental performance, researchers found no relationship between mental or physical activity and signs of Alzheimer’s disease in the brain.” The researchers think their results show that keeping fit, both physically and mentally, can stave off symptoms of Alzheimer’s even when the brain might appear to be declining.