Though some people actually love physical activity and look forward to it, for many of us, exercising is a mighty drag. Exercise has also had an added PR problem in recent years: A growing body of evidence has shown that it’s not all that good for weight loss, which was probably many people’s reason for doing it in the first place. It may help with weight a little, especially for maintenance, but by and large, if you want to drop pounds, the most effective way is to eat less, not necessarily to exercise more. That said, research in recent years has also illustrated quite persuasively what exercise is good for—and it is actually good for a number of things, including some very profound things, like reducing dementia risk. Here’s what science tells us we should probably keep exercising for, even though we may not love every minute of it.