New Boston University research just found that people who stay physically active in their 60s, 70s, and even 80s can cut their dementia risk by around 40 percent compared with less active peers.

If you are a senior, pick one simple activity you can do this week for at least 10 minutes a day: a brisk walk, climbing a few extra stairs, or light cycling on a stationary bike. Put it on your calendar like an appointment with your future brain.