What Is Sarcopenia?

Sarcopenia is the progressive loss of muscle mass and strength. The syndrome is typically associated with older adults since it usually develops due to the natural aging process. 

The prevalence of sarcopenia is estimated to range between 5-13% for people aged 60 years or older and 11-50% for people aged 80 years or older.

Sarcopenia can negatively impact your daily activity and quality of life. Difficulty in walking, climbing stairs, and carrying heavy items are common challenges with sarcopenia. You might also experience an increased risk of falls and fractures.

There are a series of tests available for the diagnosis of sarcopenia. The tests assess muscle strength, muscle quality, and physical performance.

While no medications have been approved for the treatment of sarcopenia, several lifestyle changes can manage the condition and help you regain muscle mass and strength.

Sarcopenia Symptoms

The main symptoms of sarcopenia are low muscle function, low muscle strength, and low muscle mass. The loss of muscle mass is accompanied by the accumulation of fat in the muscles, which contributes to decreased muscle strength. 

Other symptoms of sarcopenia include:

• Impaired motor function
• Difficulty in walking
• Slow walking speed
• Difficulty in carrying and lifting heavy items
• Difficulty in climbing stairs
• Increase in falls
• Physical weakness

What Causes Sarcopenia?

Sarcopenia most often occurs due to the natural process of aging. Progressive muscle mass and strength loss begin between the ages of 30 and 50 years and peaks after 60 years. About 10% of people worldwide over 60 years of age have sarcopenia.

Various mechanisms can cause the onset of sarcopenia with aging, such as:

• Insulin resistance: Aging often causes changes in body composition, leading to increased accumulation of body fat and decreased muscle mass. Such changes can lead to insulin resistance and other metabolic dysfunctions.
• Decrease in hormone levels: Aging can lead to a reduction in levels of anabolic hormones such as insulin-like growth factor-1, human growth hormone, and testosterone. These hormones play important roles in the development and maintenance of muscle tissues, and so the hormones' decline can cause sarcopenia.
• Inflammatory markers: An increase in inflammatory markers such as interleukin (IL)-6, tumor necrosis factor-alpha, C-reactive protein, and IL-1 that occurs with aging can lead to sarcopenia due to their effect on skeletal muscles.
• Neurodegeneration: Aging causes a decrease in peripheral nerve fibers, motor neurons in the spinal cord, and the number of neuromuscular junctions. Such changes in the neurological system can cause sarcopenia.

Risk Factors

Being physically inactive and not consuming enough protein are two main contributing factors to why an older adult might have sarcopenia. Obesity may be another contributing factor.

It's possible for younger people to develop sarcopenia too. Younger people with inflammatory diseases, malnutrition, and cachexia (extreme weight loss and muscle wasting) may be more likely to experience sarcopenia. Other conditions associated with the development of sarcopenia include:

• Chronic obstructive pulmonary disease (COPD)
• Chronic kidney disease
• Heart failure
• Human immunodeficiency virus (HIV)
• Diabetes mellitus
• Cancer

How Is Sarcopenia Diagnosed?

There is no single test that can diagnose sarcopenia. Diagnosis involves screening tools that help identify probable signs of sarcopenia and that assess muscle strength, quality, and physical performance. 

Screening Tools

The strength, assistance with walking, rising from a chair, climbing stairs, and falls (SARC-F) questionnaire is a screening tool that can help healthcare providers quickly identify people who might have sarcopenia. You will be asked five questions about any challenges or events (like falls) because of muscle weakness. Depending on your answers, you will be given a score from zero to two for each parameter. The highest maximum score is 10. A score of four or more might be indicative of sarcopenia and requires further testing. 

Muscle Strength Tests

There are a couple tests that can help evaluate muscle strength. One is the handgrip test. This can aid in determining overall strength in other muscles and can help to indicate any decrease in strength. Another is the chair stand test. This helps determine leg muscle strength, especially of the quadriceps. The test measures the number of times you can stand and sit from the chair without using your arms within 30 seconds.

Muscle Quality Tests

Tests that can help determine the quality—and sometimes the quantity—of muscles include:

• Magnetic resonance imaging (MRI): MRI uses magnetic fields and radio waves to provide detailed images of tissues and organs inside the body. It helps provide accurate information on total body muscle mass.
• Computed tomography (CT): CT uses a series of X-ray imaging to provide images of bones and soft tissues. It helps estimate total lean muscle mass. 
• Dual-energy X-ray absorptiometry (DXA): DXA uses X-ray technology to measure bone mineral density. It can also estimate muscle mass and bone mass.
• Bioimpedance analysis (BIA): BIA uses a weak electric current to provide information on body composition, especially muscle mass and body fat.

Physical Performance Tests

Physical performance tests help identify the severity of sarcopenia. These tests include:

• Gait speed test: The gait speed test measures the time taken to walk 4 meters at your usual pace. If the speed of walking is less than 0.8 meters a second, it might be indicative of severe sarcopenia.
• Timed up-and-go test (TUG): The TUG test measures the time it takes for you to get up from a chair, walk 3 meters away from it, and get back to the chair. A time of more than 20 seconds indicates poor physical performance.
• Short physical performance battery (SPPB): The SPPB test comprises standing balance, chair stand, and walking speed tests. The minimum score of the test is zero and the maximum is 12. A score of less than eight indicates severe sarcopenia.
• The 400-meter walk test: The 400-meter walk test involves 20-meter quick laps with two minutes of rest in between. Needing more than six minutes to complete 400 meters indicates severe sarcopenia.

Treatments for Sarcopenia

There are no approved medications available for the treatment of sarcopenia. Rather, the treatment approach for sarcopenia involves lifestyle changes. 

Physical Activity

Exercising regularly can be beneficial for muscle strength and mass for older people. Performing strength training, including weight lifting and resistance training, two or three times a week can significantly improve muscle strength and function. Before starting any exercise routine, you should consult with your healthcare provider to determine the frequency and intensity of exercise most suitable for you.

Dietary Patterns

Healthcare providers recommend an intake of 20-35 grams of protein per meal to promote muscle protein synthesis and reverse age-related loss of muscle mass and strength.

It may also be recommended that you take one or more supplements to manage sarcopenia. This is because poor nutritional status can also cause loss of muscle. Supplements that might help with sarcopenia include:

• Vitamin D
• Vitamin B
• Vitamin C
• Selenium
• Calcium
• Magnesium

How to Prevent Sarcopenia

Prevention of sarcopenia might not be completely possible since it develops as a part of the natural aging process. However, some tactics can slow the progression of the condition, such as:

• Having a well-balanced diet with high-quality proteins
• Consuming 1.6-1.8 grams of protein per kilogram of body weight per day
• Performing resistance exercises at least twice a week
• Reducing sedentary time 

Related Conditions

People with sarcopenia are at an increased risk of other health conditions. A few such conditions include:

• Cardiovascular disease (CVD): Sarcopenia can increase the risk of cardiovascular diseases in older adults. CVDs and sarcopenia influence each other through common mechanisms such as physical inactivity, malnutrition, and hormonal changes.
• Type 2 diabetes: Sarcopenia can increase your risk of developing type 2 diabetes through abnormal glucose disposal as a result of low muscle mass.
• Osteoporosis: Sarcopenia can cause significant bone loss and lead to osteoporosis. A 2022 study of women who had gone through menopause found there was a 12.9-fold higher risk of osteoporosis among those with sarcopenia compared to those without the condition.
• Cognitive impairment: Research has found that sarcopenia can cause cognitive impairment due to abnormalities in the production and secretion of molecules called myokines, which regulate brain function.
• Depression: Sarcopenia decreases the overall quality of life, which can lead to depression.

Living With Sarcopenia

Sarcopenia can significantly impact your quality of life and cause difficulties in performing daily activities. The condition can also increase your risk of falls, fractures, and hospitalizations.

How greatly sarcopenia impacts you depends on factors like age, other conditions you may have, and whether you experience any falls or fractures. Sarcopenia is associated with higher rates of complications and death after a surgery as well as death if you have diseases like end-stage renal disease, pancreatic cancer, and chronic heart failure.

Recognizing early symptoms can help manage the condition and slow its progression. Undergoing strength training and having a proper diet can help in muscle protein synthesis, improve muscle strength, and overall physical performance. 

You should also keep up with regular physicals and update your healthcare provider with any changes you think you've had in your weight, body composition, function, or health.