Every year, most older adults lose one percent of their muscle mass. But study after study suggests it’s never too late to slow muscle loss and even rebuild some of it through strength training.

That can help you stay physically active. Studies also suggest strength training can help maintain memory and prevent falls—and may contribute to a longer life. A study by UCLA in the American Journal of Medicine found that older adults with the most muscle mass were 20 percent less likely to have died during a 10- to 16-year follow-up than other study subjects.

Here are some smart, simple ways to stay strong.

Challenge Your Muscles

Resistance or strength training is the quickest way to get stronger, and you don’t have to work out like a bodybuilder. In fact, strength training can include things that don't even seem like exercise, such as carrying heavy bags of groceries.

Using your own body weight can also help build muscle: Squats strengthen your legs and modified pushups strengthen your upper body. You can also strength train on gym machines or use fitness bands or hand weights.

After you get your doctor’s okay, consider asking a professional trainer or physical therapist for a plan. Or go to growingstronger.nutrition.tufts.edu for a free program from Tufts University in Boston and the Centers for Disease Control and Prevention.

Increase resistance and the number of repetitions over time. “To improve, you have to keep stressing the muscle,” says Carol Ewing Garber, Ph.D., past president of the American College of Sports Medicine. And give muscles a day off between bouts of strength training, she says. “It makes the muscle stronger and more able to resist future injury.”

Positive results can come quickly. For example, a study published in the European Review of Aging and Physical Activity in 2015 found that older adults were stronger after just four weeks of resistance training three times per week for 40 minutes.

To maintain gains, do resistance exercises at least twice per week. “If you stop, you start losing muscle mass and strength pretty rapidly,” says Roger A. Fielding, Ph.D., a senior scientist and director of the Nutrition, Exercise Physiology, and Sarcopenia Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts. 

Aerobics Help, Too

Aerobic exercise such as walking, cycling, and kayaking or rowing can also increase muscle size and strength, according to a 2014 review of 15 studies in the journal Exercise and Sport Sciences Reviews.

It’s not yet clear how much of it benefits muscle, but “the take-home message is use it or lose it,” says Geoffrey A. Power, Ph.D., an assistant professor in the neuromechanical performance research laboratory at the University of Guelph in Ontario.

Start by aiming for at least 150 minutes of aerobic activity per week. That can be achieved with 30 minutes of moderate activity, such as walking briskly five days per week. Gradually increase the intensity, duration, and frequency as you become more fit.

Consume Vitamin D and Protein

A balanced diet is essential for overall health. But vitamin D and protein seem to be especially important for muscle strength. “There is accumulating evidence that vitamin D plays a role in preventing muscle loss and increasing muscle strength,” says Roger A. Fielding, Ph.D., director of nutrition and exercise physiology and sacropenia at the Human Nutrition Research Center on Aging at Tufts University.

And Douglas Paddon-Jones, Ph.D., of the University of Texas Medical Branch in Galveston, points out, “We need daily protein to maintain muscle as we age.”

The Institute of Medicine recommends 600 IU of vitamin D per day until age 70 (800 IU after) and 0.8 gram of protein daily for each kilogram of body weight (1 to 1.2 daily grams after age 65). That’s 47 daily grams of protein for a 130-pound woman and 58 grams for a 160-pound man.

Sun exposure is a ready source of D but raises skin-cancer risk.

Good food sources of both nutrients are salmon (preferably wild), sardines, and vitamin D-fortified milk. If you’re over 65, rarely spend time outside, or eat few foods with vitamin D, a daily 1,000-IU supplement is reasonable, says Marvin M. Lipman, M.D., Consumer Reports’ chief medical adviser.