Everyone knows that cardio exercise is crucial for overall health. But the secret to staying strong and vital for life isn't just in walking, running, biking, swimming and other forms of aerobic fitness. It's in your muscles. In a 2021 review of 16 studies from around the globe, researchers found that just 30 to 60 minutes a week of muscle-strengthening, or "resistance" exercise increased life expectancy by 10 to 17 percent. What counts as muscle-strengthening exercise? Lifting weights, yoga, Pilates, calisthenics, and even carrying the groceries (or a grandchild). Eating protein in the proper amounts, at the proper time, is also crucial for preserving muscle. As we outline in AARP's New York Times best-selling book The Whole Body Reset, science shows that women 50 and older need at least 25 grams of protein at every meal (30 grams for men) to stimulate protein synthesis, the process for building and maintaining muscle. Studies show that when people in their 60s combined this style of eating, known as "protein timing," with resistance exercise, their bodies respond as if they were in their 20s. Here's why combining resistance exercise and protein timing is so important for your health. You'll keep your brain healthy. One study looked at 970 people living in senior communities who had no evidence of cognitive decline. Researchers put the subjects through a series of strength tests,

measuring their upper and lower extremities. Over the next 3.6 years, 15 percent of the subjects developed Alzheimer's disease. But their risk was strongly determined by where they fell on the strength scale: For every 1 point increase in muscle strength, a subject's risk of Alzheimer's dropped by 43 percent.

You'll reduce your risk of future weight gain.

A low level of muscular fitness was associated with higher odds of gaining at least 22 pounds over the ensuing 20 years, one study found.

You'll keep your blood pressure under control.

In another study, higher levels of muscular strength were associated with a reduced risk of developing high blood pressure among men with prehypertension.

You'll slash your risk of heart disease.

Several studies have shown that the greater your muscular strength, the lower your chance of developing metabolic syndrome. Metabolic syndrome includes excess abdominal fat, high blood pressure, high blood sugar and high cholesterol, all heart disease factors. And the greater your muscular strength, the lower your levels of inflammatory compounds, which may also help to lower your risk of heart disease.

You'll beat back diabetes.

Higher muscle mass has been associated with better insulin sensitivity and lower risk of developing diabetes or pre-diabetes; in a study of 13,644 subjects, those with the lowest percentage of muscle were 63 percent more likely to have diabetes than those with the highest percentage.

You'll be better poised to battle cancer.

Breast cancer patients with high muscle mass have a greater chance of survivingthe disease than those who have lower muscle mass, according to a study of 3,241 women (median age: 54) with stage2 or 3 invasive breast cancer. And, in a study of men who had undergone a radical prostatectomy to treat prostate cancer, those with the lowest levels of muscle were more likely to see a recurrence of the cancer and more likely to die of the disease.

You'll stay happier.

A study of 3,000 adults ages 54 to 89 found that having a strong grip was inversely asso ciated with symptoms of depression.

Strong, healthy and happy: If that sounds like the future you imagine for yourself, it's time to make your muscles a top priority. Make sure you're getting 25 to 30 grams of protein at every meal, and talk to your doctor about starting a muscle-building fitness program.

Adapted with permission from The Whole Body Reset: Your Weight- Loss Plan for a Flat Belly, Optimum Health, and a Body You'll Love-at Midlife and Beyond, by Stephen Perrine with Heidi Skolnik, published by Simon & Schuster Copyright 2022 by AARP