What Is Sarcopenia and What Are Its Symptoms?

Sarcopenia is the age-related progressive loss of muscle mass and strength.

The main symptom of this condition is muscle weakness, which can impact quality of life, reducing the ability to perform tasks and even leading to dependency and need for long-term care. Researchers think that certain factors, such as physical inactivity and unhealthy diets, can have a hand in the development of this condition.

Sarcopenia is characterized by the generalized, progressive loss of musculoskeletal mass and muscle function (strength or performance), increasing the risk of poor quality of life, physical disability, falls, weakness, and even death.

This syndrome is usually related to aging and tends to be associated with osteoporosis, as these are two factors that can determine quality of life and longevity in older adults.

While we all tend to lose muscle mass and strength as we get older, this process is sped up in sarcopenia.

It should be noted that sarcopenia is not the same as cachexia. Cachexia is when the muscle is affected by cytokine-mediated degradation, which happens in diseases like cancer and immunodeficiency.

Sarcopenia is also not the same as muscular atrophy. In sarcopenia, the size and number of muscle fibers decrease, whereas in muscular atrophy, the size of the fibers decreases, but the number of fibers remains the same.

Experts say that rates of sarcopenia tend to increase with age: sarcopenia is present in an estimated 5-13% of people age 60 and over, a range that increases to 11-50% in people age 80 and over. The disease affects both sexes equally and is more prevalent in people with chronic conditions.

What are the symptoms of sarcopenia?

The most common sign of sarcopenia is muscle weakness, but other symptoms may include:

• Walking slowly.
• Difficulty performing daily activities.
• Reduced muscle size.
• Lack of balance and falls.
• Loss of resistance.
• Trouble climbing stairs.

But why does sarcopenia happen? Researchers say that as we get older, our body goes through changes that play a key part in the development of this disease. For example, we do not produce the same amount of proteins that muscles need to grow (causing muscle cells to shrink), and changes occur in some hormones, such as testosterone and insulin-like growth factor (IGF-1), which affect muscle fibers.

Although aging tends to be the primary driver of sarcopenia, researchers have discovered other possible risk factors:

• Rheumatoid arthritis.
• Malnutrition or inadequate protein intake.
• Decreased ability to convert proteins to energy.
• Decrease in the number of nerve cells that send messages from the brain to the muscles to tell them to move.
• Chronic diseases: chronic obstructive pulmonary disease (COPD), kidney disease, diabetes, cancer, or human immunodeficiency virus (HIV).
• Physical inactivity.
• Obesity.
• Reduced hormone levels.
• Insulin resistance.

Diagnosis and treatment

To diagnose sarcopenia, a health care professional can perform physical exams and conduct a self-reported symptom questionnaire called SARC-F, which stands for:

• S: Strength.
• A: Assistance in walking.
• R: Rise from a chair.
• C. Climb stairs.
• F: Falls.

They may also do other muscle strength tests, such as:

• Handgrip test: To identify deficits in overall muscle strength.
• Chair stand test: To measure the strength of the leg muscles, especially the quadriceps.
  
• Gait speed test.
• Short physical performance battery (SPPB): Involves three timed tasks: a chair stand test, standing balance test, and gait speed test.
• Timed-up and go (TUG) test: Measures the time it takes to rise from a chair, walk three meters away from the chair, walk back to the chair, and sit down.

Other tests they may do include:

• Dual-energy X-ray absorptiometry (DEXA or DXA): Uses low-energy X-rays to measure muscle mass, fat mass, and bone density.
• Bioelectrical impedance analysis (BIA): Measures body fat in relation to lean body mass.

Treatment for sarcopenia usually involves lifestyle changes, such as adopting a healthy diet coupled with regular exercise.

As for medications, the US Food and Drug Administration (FDA) has not approved any drugs to treat sarcopenia. However, researchers are studying the possibility of using hormone supplements to increase muscle mass.

Can sarcopenia be prevented?

Since this condition occurs as part of the natural aging process, experts say that it cannot be prevented—but you can take steps to delay its progression. These include:

• Maintaining a healthy diet rich in fruits, vegetables, legumes, grains, and lean meats.
• Doing regular exercise, especially resistance activities.
• Having routine physical exams, which can help identify any health changes or problems early on, when treatment is more effective.

Sources: National Library of Medicine; Cleveland Clinic; National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS); National Cancer Institute (NCI).