Adults who want to hold onto muscle as they age should focus on four practical habits — eating enough protein, lifting weights, sleeping well and staying active — according to a New York-based fitness coach who works primarily with clients between 35 and 55 years old.
Jacob Zemer told Fox News Digital that the advice has taken on new urgency as more Americans use GLP-1 medications for weight loss. Those drugs have been linked to a loss of lean muscle, particularly during rapid weight loss, making strength preservation a priority for users and non-users alike.
Zemer said the biggest driver of age-related muscle loss is not biology alone but lifestyle. In the teen years and twenties, people tend to run around and take part in activities that naturally build muscle. That changes as careers and families take over.
«You simply become more sedentary, which lowers your metabolism and your level of activity, so you're going to have less muscle,» he said.
Hormonal shifts add another layer. As people approach their 40s, hormone levels change for both men and women, Zemer noted. That means the body partitions calories less toward protein and muscle building and more toward storing fat.
«We see this all the time … people start to store fat in their tummies, and they start have less muscle,» he said.
Zemer frames muscle as a kind of retirement account. People should aim to build muscle well into their 50s so they have reserves to draw on in their 60s, 70s and 80s. In the 30s and 40s, when lifestyle has already changed, that requires being more strategic — going to the gym and training deliberately rather than relying on daily activity.
The first habit is protein. Protein stimulates muscle protein synthesis, the body's process of repairing and building muscle, and adequate intake can reduce the risk of sarcopenia, the age-related loss of muscle mass and strength. Needs vary by age, activity level and fitness goals. Zemer said sedentary people do not need to obsess over protein, but those who strength-train should aim for roughly 0.8 to 1 gram per pound of body weight.
The second is strength training. The U.S. Physical Activity Guidelines recommend that adults train all major muscle groups — legs, hips, back, abdomen, chest, shoulders and arms — at least two days per week. The Centers for Disease Control and Prevention advises using moderate or greater intensity until it becomes difficult to complete another repetition with good form. The guidelines also suggest pairing strength work with 150 to 300 minutes of moderate aerobic activity, or 75 to 150 minutes of vigorous activity, each week.
Zemer said lifting weights is not only about building muscle but preserving it. Even a busy week with two 30-minute sessions may not add new muscle, but it is enough to maintain what exists.
For beginners, he recommends basic functional movements. Body-weight exercises such as squats, lunges, push-ups and pulling movements build strength for everyday activities. Carrying weighted objects — a farmer's carry — can improve grip, balance and stability. People who feel intimidated by the gym can work with a qualified trainer for a few sessions to build confidence and refine technique.
The third habit is sleep, which Zemer called perhaps the most difficult strategy to maintain. He emphasized seven to nine hours of quality sleep. Occasional short nights will not cause muscle loss, but consistent serious sleep deficiency — around five hours a night — is when rapid muscle loss appears.
The fourth habit is avoiding total inactivity. Zemer said the worst thing people can do, even when injured, is to stop doing anything. They should find movements they can perform even if something hurts or their knees are not what they used to be. Regular movement helps slow age-related muscle loss, while sedentary behavior is associated with rapid declines in muscle mass and strength.
Zemer said the strategies are especially important for people taking GLP-1 medications for weight loss. Without strength training or adequate protein, those drugs can accelerate the loss of lean muscle alongside fat.
«If you are on a GLP-1, just remember you're accelerating the rate of fat loss, but you're also accelerating the rate of lean muscle,» he said. «You want to make sure you're getting that protein and training, so that you are not losing muscle on top of the fat loss.»