Muscle health is linked to how well we fight off disease and our longevity. But healthy muscles aren’t just about the size of a bicep or how much we weigh.
An international team of kinesiologists and nutrition experts recently urged doctors to pay more attention to skeletal muscle quality and the ratio of muscle to fat as a key to “metabolic regulation, immune function and overall vitality and functioning.”
“Muscle health estimation could be as important as measuring somebody’s blood pressure,” said longevity expert Dr. Nicolaas Deutz, a professor in the Department of Kinesiology and Sport Management at Texas A&M University and a co-author of the expert review. Kinesiology is the study of physical activity and body mechanics.
Healthy muscles not only help you move safely, they’re also the body’s main storage system for blood sugar, which maintains an active metabolism and lowers inflammation in the body.
Muscle health is usually associated with muscle size in younger people, but that relationship becomes less clear as we get older, said Deutz.
In fact, mass is only a part of overall muscle health. For instance, women generally have lower overall muscle mass than men, yet their muscle health is generally comparable to men’s.
A more complete picture of muscle includes strength, balance, physical function, activity levels and the amount of fat stored within the muscle itself, said Dr. Fatima Cody Stanford, an obesity medicine physician-scientist at Mass General Brigham.
How to prevent muscle loss
There’s growing awareness of how muscle health plays a role in longevity and metabolic diseases such as Type 2 diabetes, especially in the wake of the phenomenal popularity of GLP-1 medications. Drugs such as Ozempic and Zepbound have been shown to improve blood sugar, blood pressure and cardiovascular risk, but they’re also linked to loss of both fat and lean mass, including skeletal muscles.
Stanford, who is also associate professor of medicine and pediatrics at Harvard Medical School, said people taking GLP-1s need adequate nutrition to preserve muscle function.
“As a person loses substantial body weight, the body requires less muscle to carry that weight, and reductions in fat within muscle may improve muscle quality and function,” Stanford said. “At the same time, older adults, individuals with frailty or low baseline muscle mass, and people who are losing weight rapidly warrant particularly close attention to strength, function, protein intake and resistance exercise.”
A sufficient amount of high-quality daily protein — including fish, poultry, eggs, dairy, tofu, beans, lentils, nuts and seeds — helps protect against muscle loss, Stanford said.
The U.S. dietary guidelines encourage people to prioritize protein with nutritious, minimally processed foods at every meal, recommending 1.2 to 1.6 grams of protein per kilogram of body weight.
Staying active — working in the yard, walking or weight training — strengthens different muscle groups, Deutz said.
If lifting heavy gym weights isn’t appealing, resistance exercises can effectively preserve muscle strength and function, particularly during weight loss.
“Body-weight exercises, resistance bands, machines or supervised strength work can all be appropriate depending on the individual’s mobility, fitness level and medical history,” Stanford said.
How to measure muscle health
Muscle power is the ability to produce force quickly, and handgrip strength is one of the simplest ways to measure it.
“An often-overlooked consideration is muscle power — the ability to produce force quickly, which declines earlier and more rapidly with aging than muscle strength,” said Stephen J. Carter, Ph.D., associate professor in the Department of Kinesiology at the School of Public Health — Bloomington Indiana University. “From a practical perspective, muscle power is more relevant to daily life than simply strength.”
Grip strength measures the force generated when squeezing a handheld tool called a dynamometer.
While “low” strength depends on factors like age and BMI, a large analysis of grip strength of over 20,000 older men and women defined it as less than 57 pounds for men and 35 pounds for women.
Fortunately, targeted resistance training can successfully improve the numbers.
Carter recommended resistance training, such as free weights, weight machines, resistance bands or body-weight exercises like push-ups, two to three times weekly, progressing gradually to a higher intensity to build more muscle.
Other functional tests can help evaluate broader endurance, power and mobility:
- The 6-Minute Walk Test: Measures how far a person can walk in six minutes. It’s a gauge of lung and cardiovascular fitness.
- The Timed Up and Go Test: Assesses fall risk and mobility, and can easily be performed at home.
- The 30-Second Chair Stand Test: Tests lower-body strength by counting the number of times someone gets up from a chair in 30 seconds without using arms.
- The 5-Repetition Sit-to-Stand Test: Measures lower-body strength and mobility by timing how fast someone can perform five repetitions from sitting to standing position without using arms. It’s a measure of balance, muscle strength and flexibility.
