Being physically active can lift mood, help you maintain a healthy weight, and keep your muscles strong—and mounting evidence suggests that working out may have brain benefits as well.

Now, a study published this week in the journal Neurology: Clinical Practice, is helping to determine how much exercise you may need for better brain power.

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Based on reviews of 98 randomized controlled trials, researchers from Brazil, Spain, and the U.S. found that people started to show some improvement in brain function—they were unable to pinpoint exactly how much—after a minimum of 52 hours of exercise. Their findings were true for those with cognitive impairment as well as those with normal cognition.

“Once you’re around that 50-hour mark, you would expect to see some increase in mental sharpness,” says Joyce Gomes-Osman, P.T., Ph.D., the study’s lead author and an assistant professor in the departments of physical therapy and neurology at the University of Miami Miller School of Medicine.

In the studies reviewed, exercise programs lasted about six months on average, but that doesn’t mean it’s necessary to get those 52 hours over a half-year.

What’s more important, Gomes-Osman says, is understanding that it takes a while for any thinking-related benefits of exercise to take hold. “These are things that happen slowly,” she says, with consistent exercise over time. 

Another takeaway from the new study—and some previous ones—is that while most of the research on the exercise-brain connection has been on aerobic workouts, other kinds of exercise also appear to be beneficial.

For example, a recent analysis from the University of Canberra in Australia found that some nonaerobic activities can also help improve brain function in people older than 50. 

“Even when people did have some level of decline already, they were actually able to improve their cognitive function,” says the Canberra study’s author, Joseph Northey, a Ph.D. candidate in sport and exercise science. 

Here, for Alzheimer’s and Brain Awareness Month, is advice on how to optimize your exercise routine to help brain health.

Take a Brisk Walk

If you don’t exercise now, it’s easy to start. Just walk out your door and keep going.

It’s fine to start small. Build up from 10 minutes walking a day until you get to at least 30, says Elissa Burton, Ph.D., a research fellow in the school of physiotherapy and exercise science at Curtin University in Australia.

And if you can, pick up your pace. Getting your heart rate up will maximize the benefits to your brain, according to Helen Macpherson, Ph.D., a dementia research fellow at Deakin University in Australia. That means you should be exercising at an intensity where you start to find it difficult to have a conversation.

Do More Than the Minimum

The Centers for Disease Control and Prevention recommends that older adults get 150 minutes of this sort of moderately intense aerobic exercise each week, which is five 30-minute workouts. But the biggest boost in brain health in the Canberra study was linked to exercise sessions of 45 to 60 minutes.

So try consolidating some workouts into a longer session. Or gradually work up to 45 to 60 minutes, five days per week.

Try Tai Chi

This Chinese martial art, which consists of slow, rhythmic movements, was one of several types of exercise tied to improved cognitive functioning in the recent Canberra study.

Plus it’s low-impact, which can be good for people who haven’t been active in a while, Northey says. It’s also easy on your joints.

To learn the proper technique, it’s best to seek out a local class, Northey says. You can find instructors near you who are certified by the American Tai Chi and Qigong Association.

Resistance Training Can Help, Too

Resistance training, exercise that causes muscles to contract, is meant to strengthen, but it may also help protect against cognitive decline. And you don’t have to use weights or other equipment, Northey says. The CDC recommends resistance training at least twice per week. Here are three tips to get you started:

Stand up, sit down, repeat. As long as you’re steady on your feet, try standing up from a chair without using your hands. Do this in sets of five or more any time you find yourself sitting around the house.

Make daily tasks harder. Choose stairs over elevators and escalators. You’ll get an aerobic workout and build muscle at the same time.

Join a class. Northey’s study found that group programs incorporating resistance and aerobic training were beneficial for the brain. Check out the offerings at your local YMCA or senior center, and remember to talk with your doctor before you start any new exercise program.

Editor’s Note: This article also appeared in the September 2017 issue of Consumer Reports On Health. It has since been updated to reflect new research on exercise and brain health.