After 40, muscle mass begins to decline gradually, affecting metabolism, bone density and balance. The shift is subtle. There is no single moment when lifting a suitcase becomes difficult or getting up from the floor takes longer. Instead, strength and stability erode slowly — until everyday movements begin to
feel harder.
From a medical standpoint, that decline is not inevitable.
“Use it or lose it really comes into play here,” says Dr. Jason Pothast, a sports medicine physician with MedStar Health who is based in Olney. “We do know that strength gradually declines after 40, but a lot of that is because people stop using it. If you stay active, you can maintain — and even build — strength at any age.”
Even into later decades of life, the body remains responsive.
“We’ve shown that even 90-year-olds can get in the gym and grow muscle mass and strength,” Pothast says.
That ability has broad implications for health. Beyond building muscle, strength training supports overall physical function.
“It improves bone health, muscular fitness and overall quality of life,” Pothast says. “Exercise can lower the risk of cardiovascular disease, certain cancers and even all-cause mortality.”
Muscle also plays a central role in resilience — the body’s ability to move, react and recover.
“The more muscle mass one has, the more resilience one has overall,” says Rebecca Schumer, a MedStar Health physical therapist who sees patients in Montgomery County. “It allows independence with daily activities, reduces fall risk and helps protect
against injury.”
That resilience becomes increasingly important with age. Without it, small physical challenges — stepping off a curb, catching your balance — can become riskier.
“If we have to quickly cross the street or navigate a curb, that strength is what keeps us safe,” Pothast says.
Muscle also helps regulate metabolism in ways that cardio alone cannot.
While aerobic exercise burns calories during the activity, strength training continues to work after the session ends.
“Your muscles break down during lifting and then repair and rebuild afterward,” Pothast says. “That increases your metabolism, so you continue to burn calories even after you’ve
finished exercising.”
That process helps keep weight in check and can reduce the risk of obesity, diabetes and heart disease. In some cases, lifestyle changes that include strength training can even reduce the need for medication.
“Some people with Type 2 diabetes can improve enough to come off medications, depending on their situation,” Pothast says.
Beyond metabolism, strength plays a critical role in protecting joints — particularly in the knees, hips and lower back.
“If you develop stronger muscles around a joint, those muscles take
on more of the load,” Pothast says. “They absorb the shock instead of the joint itself.”
That dynamic is echoed in physical therapy settings.
“Muscles are our dynamic support system,” Schumer says. “Without that support, stress shifts to the joints,
which can lead to pain and breakdown over time.”
For many patients, that connection becomes clear only after problems develop.
“Strength training is critical to reducing risk of injury and building a resilient body,” Schumer says. “It’s amazing how the body responds when you start doing it consistently.”
Strength also influences balance — a key factor in preventing falls, one of the most serious risks for older adults.
“If someone stumbles, a stronger person is more likely to react and catch themselves,” the therapist says.
For people who have been mostly sedentary, getting started can feel daunting. But experts emphasize that it does not require an intense or complicated routine.
“Go low and slow,” Pothast says.
Starting with lighter weights and higher repetitions allows the body to adapt without injury. Over time, strength can be built gradually.
“You don’t want to shock your system by jumping straight into heavy weights,” he says.
Exercises that engage multiple muscle groups — such as squats, pushups and pulling movements — offer the greatest benefit. Working all major muscle groups two to three times a week is generally recommended.
For beginners, guidance can help.
“If someone is new, working with a trainer or using structured programs can help establish proper technique,” Pothast says, noting that resources such as the federal “Move Your Way” initiative can provide free guidance.
There are also common mistakes that can undermine progress.
One of the most frequent is doing too much, too quickly.
“People get excited and start programs that are too intense or that they don’t enjoy,” Pothast says. “Then they burn out after a few weeks or months.”
Consistency matters more than intensity. A routine that can be maintained over time is far more effective than short bursts of effort.
“Do something that you like and can stick with,” he says.
From a physical therapy perspective, technique is just as important as consistency.
“Form is critical,” the therapist says. “If form breaks down, the risk of injury increases.”
Strength training should also be deliberate, not rushed.
“It’s not cardio,” Schumer says. “You need rest between sets so each repetition is done properly.”
Understanding the body’s signals is also key.
Normal muscle soreness typically appears within a day or two after a workout and fades within a few days. Pain that persists longer — or sharp, sudden pain — may indicate an injury.
“If soreness lasts beyond about three days or continues to worsen, it’s worth getting checked out,” Pothast says.
Certain symptoms require more immediate attention.
“Chest pain or significant shortness of breath are red flags that should prompt medical evaluation,” he says.
Ultimately, strength training is less about appearance and more about preserving independence.
It supports the ability to carry groceries, climb stairs, maintain
balance and recover from small
missteps — the everyday actions that shape quality of life.
And while aging is inevitable, how the body responds to it is not entirely out of our control.
“We need consistency,” Pothast said. “It’s something you build into your routine over your lifespan — not just for a few months, but something you stick with long term.”
