If you only have time for one exercise, fitness experts say, do this one

As you age, you naturally lose muscle mass, so it’s important to strength train to stay strong. Ideally, you should work all of the major muscle groups in your upper and lower body at least twice a week.

But if you have time for only one exercise, you’ll get the most bang for your buck by doing a set of squats, experts say.

“The squat is the most important exercise for seniors,” says Eric Daw, a personal trainer dedicated to older adults and founder of Omni-Fitt in Toronto, Canada. “When you have to go to the washroom, that’s a squat. When you get in the car, that’s a squat. Every time you sit down or stand up, that’s a squat. If you don’t do them well, it affects the way you live.”

Squats strengthen all of the muscle groups in your legs, including your calves, quadriceps, hamstrings and glutes, as well as muscles in your lower back and core. Those muscles provide the foundation for most activities of daily living, such as getting off the toilet, climbing a set of stairs and simply standing up from a chair.

Squats can also help protect your joints, improve your balance and prevent falls, says Denise Austin, health and fitness expert and creator of DeniseAustin.com.

“Squats are one of the best overall exercises,” she says. “They strengthen the major muscles of the lower body we need to keep strong and also protect two joints we need help with on a regular basis — our knees and our hips.”

Research shows a link between strong leg muscles and longevity. One study that followed healthy adults 70 and older for more than six years found that those who had greater quadriceps strength had a lower risk of early death. Another study revealed that your ability to sit on the floor and then get up without using your hands or knees could predict mortality.

Here’s how to get started with squats:

1. Get in position

If you’re new to squats, choose a spot where you can hold on to the kitchen counter, a table or another steady surface. Holding on for stability makes it easier to focus on your form without worrying about your balance, Austin says.

Set your feet about shoulder-width apart or a little wider. (If you have hip issues, it’s OK to have your legs a little farther apart.) Toes should face slightly outward.

2. Lower into a squat

Keeping your back straight, chest up and heels planted, push your hips back like you are sitting in a chair.

Try to keep your weight evenly distributed on both feet as you do the exercise, with your weight mostly on your heels, not your toes, says Lori Michiel, founder of Lori Michiel Fitness, which specializes in senior fitness in the home.

Make sure your knees do not extend forward over your toes, because that can hurt your knees.

If you have knee or hip issues, you don’t need to do a deep bend. The coming-up part of the exercise is what really builds strength, Austin says.

3. Repeat

Aim for two sets of eight to 10, at a tempo of two seconds down, two seconds up. Inhale on the way down and exhale on the way up. As your body tires at the end of the set, make sure you’re not hunching over or letting your knees cave in.

For the best results, do the exercise two or three times a week.

4. Get your arms in play

As you start to build strength, you can try doing your squats without holding on to anything. For balance, let your arms rise parallel in front of you on the downward part of the squat, then drop them to your sides when you stand up, Austin suggests. You can see Austin demonstrating how to do a mini-squat in the video below.

Another option is to cross your arms across your chest. That can help keep you upright if you tend to hunch over, Daw says.

5. For a greater challenge, add resistance

Once you can do two sets of 15 without feeling any muscle soreness afterward, you’re ready to add some weight.

The easiest way is to hold a pair of dumbbells, Daw says. “That’s how you build strength faster,” he says. Start with low weights and build up.