How a sedentary lifestyle can cause muscle atrophy and what you can do to prevent it

• Muscle atrophy is when muscles shrink and weaken due to lack of use.
• Other symptoms of muscle atrophy include asymmetry and impaired balance.
• In most cases, muscle atrophy can be reversed with general exercises like walking and biking.

Muscle atrophy is a consequence of not using your muscles enough. When you stop working a certain muscle, your body repurposes the protein in it for other bodily functions.

As a result, the unused muscle shrinks and weakens, making it difficult to use. Muscle atrophy can happen to anyone and affect any muscle in the body, says Cory Oswald, a physical therapist at the Iowa Clinic.

But luckily, in most cases, you can treat muscle atrophy by building those muscles back up through exercise, physical therapy, and more.

What is muscle atrophy?

Muscle atrophy is when muscles shrink in size because they are not being used, such as when you're on bedrest or confined to a desk for hours, multiple days of the week.

Besides visible muscle loss, other symptoms of muscle atrophy include:

• Muscle weakness, which is the main symptom. "Going up and downstairs, walking, getting up out of a chair, lifting things overhead into the cupboards at home - all those simple, daily tasks may become more difficult," says Oswald.
• Asymmetry: For example, if a knee injury prevents use in one leg, the muscles in that leg may become smaller than those in your other leg, says Alexis Colvin, MD, professor of orthopedics at Mount Sinai Health System.
• Impaired balance and coordination: For example, if the muscles in your legs, core, or back are weaker, they can't support your weight as well.

How long it takes for muscles to atrophy depends on the person and the cause of atrophy. But if someone who is normally active is suddenly unable to use a part of their body, those muscles can start to atrophy in as little as a couple of weeks, Oswald says.

Note: While muscle atrophy generally is not life-threatening, it may be a sign of other health problems, like ALS, that could become life-threatening, Oswald says.

What causes muscle atrophy?

Muscle atrophy is primarily due to lack of use, which can be caused by:

• Injury or surgery, which prevents you from using part of your body. For example, If you have knee surgery, that leg may need to be immobilized in a brace, and your muscles may atrophy from disuse, Oswald says.
• Aging. Age-related muscle loss is called sarcopenia, and it can lead to falls and other injuries. It's estimated to affect 5% to 13% of people aged 60 to 70.
• Muscular-related medical conditions like multiple sclerosis, ALS, Guillain-Barre syndrome, spinal cord injury, and stroke. These conditions limit mobility or affect the nerves that control muscles.

Can muscle atrophy be reversed?

Most of the time, muscle atrophy can be reversed in about two to four months, though timing will depend on individual circumstances, Colvin says.

The most common ways to strengthen, and thus treat atrophied muscles include:

• Engaging in general exercise. Try walking, biking, and avoiding being seated for more than 30 minutes at a time, Oswald says.
• Trying physical therapy. A physical therapist may prescribe specific exercises that are tailored to that area of the body.
• Considering electrical stimulation, which involves a device that uses electrical currents to stimulate muscle without moving the body. In fact, a small 2015 study compared 70-year-olds who performed leg press exercises with those who underwent electrical stimulation. After nine weeks, the study found that electrical stimulation was better at counteracting atrophy, but both therapies improved muscle function and performance.
• Looking into surgery. In some cases, atrophy can cause a contracture, a condition in which the affected joint becomes stiff. In that case, surgery may be needed to correct it, Oswald says.

However, if muscle atrophy is due to neurological damage like a stroke, it may be irreversible. That's because the brain is no longer able to send signals to the muscle so it can be used.

Insider's takeaway

Muscle atrophy is a condition in which muscles begin to waste away due to disuse. It can have various causes like immobility from surgery, a neurological problem like a stroke, or aging.

Besides visibly small muscles, other symptoms of muscle atrophy include pain, swelling, and weakness.

If you think you have muscle atrophy and don't suspect it is due to an underlying medical condition, there is no need to see a doctor. Instead, muscle atrophy can be reversed with exercise or other treatment.

However, if you have a medical condition or suspect you may have one, reach out to a doctor who can find the best course of treatment for you.