Q: I know that working out is good for my brain, but just how much exercise do I need to get the benefits?

A: It’s great to hear that you’re keeping this lesser-thought-of (but very important benefit) of staying active in mind when crafting your workout plan. Not only does research show that exercise improves cognitive function and reduces your risk of Alzheimer’s disease over the long haul, but there’s also evidence to suggest that it can sharpen your memory and help your brain process information more efficiently.

If you’re looking for an immediate boost in alertness, aim for a quick, moderate workout. Research suggests that just 20 minutes of cardiovascular exercise at 60 to 70 percent of your maximum heart rate could help improve your memory and sharpen your ability to think about and respond to tasks. 

For longer-lasting benefits, spending a bit more time exercising—and staying consistent with your workouts—is key. Researchers at Harvard Medical School studied the brains of people who broke a sweat for an hour, three days a week over the course of six months. These exercisers increased the volume of their brain’s gray matter (which processes information), as well as the size of their hippocampus (the area of the brain that controls memory and learning). Studies show that even 40 minutes of moderate exercise three days a week builds up this part of the brain—important, considering that it tends to shrink as we age.

Strength training benefits the brain (so try to do it twice a week), but aerobic exercise seems to have the biggest impact. This doesn’t mean you need to hit the cardio machines at the gym every day even if you don’t enjoy it—anything that gets your heart rate up with help.

Dancing, for example, can be fun, social and challenging, and it may lower your risk of cognitive decline and dementia; consider signing up for a partner-dancing class, like salsa or tango. Taking a brisk walk or even going for a hike are also great aerobic options, and being in nature may provide another boon for your brain: Outdoor “natural” environments appear to stoke creativity and strengthen cognitive powers better than outdoor urban environments.

It’s also important to keep in mind that stretching and balance routines have their place in a well-rounded fitness plan. Yoga is a great way to incorporate both into your workout, and it may also help your mind. The practice encourages you to have such an awareness of your body’s movements that your focus on external stimuli naturally quiets down. In this way, yoga is a wonderful mind-body practice.