That's muscle slipping away, and you can build it back.

What Is Sarcopenia?

From the time you are born to around the time you turn 30, your muscles grow larger and stronger. But at some point in your 30s, you start to lose muscle mass and strength. You keep losing muscle as you age. If you lose so much strength and muscle mass that you struggle with basic daily activities, you may be diagnosed with age-related sarcopenia or sarcopenia with aging.

Everyone loses muscle with age, typically about 3%-5% each decade after age 30. Inactive people lose the most. The loss can become more noticeable and start to speed up at around age 60. After age 80, studies suggest somewhere between 11% and 50% of people have sarcopenia.

One reason that the estimates vary so much is that different definitions and ways of diagnosing sarcopenia are used by doctors and researchers around the world.

 Sarcopenia can be a serious problem. Once you've lost a lot of muscle and strength, you may struggle to do things such as getting out of chairs, opening jars, or carrying groceries. You also can become frail and have a higher risk of falls, broken bones, disability, and death.

Sarcopenia Causes

 While not everyone who lives longs enough will develop sarcopenia, the major cause of sarcopenia is aging.

 Here are some of the things happening in our bodies as we age that might contribute to sarcopenia:

• Reduction in nerve cells responsible for sending signals from the brain to the muscles to start movement
• Lower concentrations of some hormones, including growth hormone, testosterone, and insulin-like growth factor
• A decrease in the ability to turn protein into energy
• Increases in inflammation, partly due to disease
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Sarcopenia Risk Factors

The reasons some people develop sarcopenia while others don't are complex, though age and inactivity are major risk factors. Here's a little more information about each risk factor.

Age

Sarcopenia is rare before age 60, though the process of losing muscle begins decades before that. In addition to the biological changes that are part of the aging process, older adults are likely to have additional risk factors, such as inactivity, a poor diet, and chronic disease, which contribute to loss of muscle and strength.

Sedentary lifestyle

Studies suggest that staying active as you age can cut your risk of sarcopenia significantly. The more time you spend sitting or lying down during the day, the more muscle mass and strength you are likely to lose. Spending a lot of time inactive may contribute to lost muscle and strength even if you exercise during other parts of the day.

Diet

A poor-quality diet appears to contribute to sarcopenia. Scientists are still sorting out the most important dietary factors, but low intake of protein is a suspected contributor because the body has increasing trouble turning protein into energy as we age. Some, but not all, studies show a link between eating too little protein and developing sarcopenia. Other dietary habits, including diets low in fruits and vegetables, may also play a role. Diets with a lot of ultra-processed foods — manufactured products with high levels of sugar, salt, additives, and unhealthy fats — also have been linked to low muscle mass.

In general, older adults who are malnourished, because they eat too little or eat a diet that doesn't provide adequate nutrients for their needs, are at higher risk for sarcopenia and decline more rapidly when they have it.

Obesity

Some of the same factors that raise the risk for sarcopenia, such as inactivity and a poor diet, can lead to obesity. When you have both conditions, doctors call it sarcopenic obesity. Obesity appears to worsen sarcopenia. High levels of body fat increase inflammation and change how your body responds to a hormone called insulin, both of which can speed up muscle loss. Obesity can also make it harder to stay active, leading to a cycle of muscle loss and fat accumulation.

Chronic illness

Having a chronic disease such as chronic obstructive pulmonary disease (COPD), kidney disease, diabetes, cancer, or HIV increases your risk of sarcopenia.

Sarcopenia Symptoms

These are some of the most common symptoms of sarcopenia:

• Muscle weakness
• Loss of stamina, or staying power, when you are active
• Slow walking
• Trouble performing daily activities
• Trouble climbing stairs
• Loss of balance
• Falling
• Noticeably shrinking muscles

What is the difference between sarcopenia and muscular atrophy?

Muscular atrophy means loss of muscle mass. When you have age-related sarcopenia, you have muscular atrophy. But muscular atrophy isn't always sarcopenia because it can have causes other than aging. For example, someone on bed rest or with a very inactive lifestyle can lose muscle mass at any age. Muscle loss also can be caused by medical conditions that affect movement, such as a stroke, and by conditions that damage nerves needed for muscle function, such as spinal cord injuries and multiple sclerosis.

Sarcopenia Diagnosis

To diagnose sarcopenia, your doctor will start by giving you a physical exam and taking your medical history.

You may also fill out a questionnaire that screens for sarcopenia — giving your doctor a good idea of whether further testing for the condition makes sense. A widely used questionnaire is called the SARC-F. SARC-F stands for:

• S: Strength
• A: Assistance with walking
• R: Rising from a chair
• C: Climbing stairs
• F: Falls

So, you'll be asked how much trouble you have:

•  Lifting or carrying 10 pounds
•  Walking across a room without a cane, walker, or other assistance
•  Rising from a chair or bed
•  Climbing stairs

You'll also be asked if you've fallen in the past year and, if so, how often.

Based on your answers, you'll get a score of between 0 and 10, with 10 suggesting the highest chance that you have sarcopenia, and any score of 4 or more suggesting more follow-up is in order.

Follow-up tests fall into two broad categories: those that look at how strong and mobile you are and those that measure your muscle mass.

Tests that look at your strength and your ability to move as you perform everyday activities include:

Hand grip test. In this test, you'll be asked to squeeze a device called a hand dynamometer, as hard as you can, one hand at a time. The device will show how much force you can apply with your hands, which is considered a good marker for how strong you are overall.

Chair stand test. You'll be asked to sit and stand from a chair as many times as you can, without using your arms, in 30 seconds. This is a test of your leg strength.

Walking speed test. This test typically looks at how long it takes you to walk about 13 feet (4 meters) at your usual speed.

400-meter walk test. In this longer walking test, you'll be asked to complete 20 laps of 20 meters each as quickly as possible, with no more than 2 minutes rest between each lap.

Timed up and go test. This test times you as you rise from a chair, walk about 10 feet (3 meters) away, return, and then sit back down.

Short physical performance battery. This combines three timed tests: standing from a chair, standing balance, and walking speed.

A variety of imaging tests can be used to measure muscle mass and confirm sarcopenia. These can include:

Dual-energy X-ray absorptiometry (DEXA or DXA). This test, also commonly used to measure bone density, uses low-dose X-rays to measure your muscle and fat masses as well.

Bioelectrical impedance analysis (BIA). This widely available and inexpensive test can measure body composition, including muscle and fat, using a mild electrical current.

MRI or CT scans. While these can produce highly accurate measurements of total body muscle mass, they are less widely used for confirming sarcopenia because of their limited availability and high cost.

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