Have you ever walked through a crowd of people and noticed people whizzing by you in way too much of a hurry? Or, on the other hand, you might get wedged behind someone puttering along as if they have nowhere to be. Walking speed can be annoying when you get stuck in the middle, but it can also convey information about a person’s physical and cognitive health.

In fact, “gait speed,” or how fast a person walks, can help gather a picture of cognitive health and risk for cognitive decline. In one study of gait speed, people with slower walking speeds had smaller brains and thinner brain cortexes. Their brains also showed more signs of risk factors for dementia. The slower walkers performed worse when tested on memory, reasoning, and processing speed.

If you’re always the one lagging behind, there’s good news. You can improve your walking speed by improving your overall physical fitness. One study of 1740 people over the age of 65 looked at how improving physical fitness might reduce risk for Alzheimer’s disease. The group of people who originally performed poorly on a walking speed test, but gradually improved their fitness by exercising 3 times a week, reduced their risk for Alzheimer’s.

You don’t need a gym membership or workout equipment at home to start exercising. Start slowly, with a walk around the block, dancing to your favorite song in your living room, or a few wall push-ups. Then, you can gradually work your way up to working out 30 minutes at a time.