What is Sarcopenia?

May 18, 2022
What is Sarcopenia?

Patients often come in with the goal to lose body fat, but after they get a body composition analysis done, some learn that they are losing not just fat but also significant muscle mass.  Sarcopenia, from the Greek meaning “loss of flesh,” is an age related, involuntary loss of muscle mass and strength that impacts over 10% of adults over age 50 and over 50% of those older than 80. Unfortunately, sarcopenia correlates with shortened life expectancy and limits the ability of sufferers to perform routine activities.  This is an introduction to sarcopenia and sarcopenic obesity.

After age 30, people start losing muscle mass. All humans lose muscle mass and function as they age including athletes, although sedentary people tend to lose muscle faster than physically active people.  Also, the “quality” of the muscle changes with age. With age there is a decline in quality and number of muscle cells, as well as force.

There is a connection between sarcopenia and functional status.  Sarcopenic women have 3.6 times higher rates of disability, and men have 4.1 times higher rates when compared to those with normal muscle mass. There is a significantly greater risk of using a cane or walker and a history of falling in the elderly with sarcopenia.

Sarcopenic obesity is a type of sarcopenia that involves muscle and strength loss with high fat mass. Often those with sarcopenic obesity have a normal or nearly normal BMI with a high percentage body fat and low muscle mass. 

The cause of sarcopenia is still not fully understood but there are many possible mechanisms.  Sarcopenia is thought to be caused by an imbalance of signals for muscle growth (anabolic) and muscle breakdown (catabolic).  Some of the factors that are thought to speed up muscle loss include:

  • Loss of “α-motor neuron” input to muscle,
  • Loss of body weight after age 60,
  • Physical activity decline with age,
  • Protein deficiency or unbalanced diet,
  • Inflammation including that caused by chronic diseases such as rheumatologic diseases, lung diseases, and inflammatory bowel disease, 
  • Stress,
  • Age-related hormonal changes, including decreases in estrogen, testosterone, and growth hormone,
  • Insulin resistance which increases with age, fat mass (especially visceral fat), and physical inactivity.

There is still a lot to learn about what causes sarcopenia and how to treat or prevent this condition.  

How can I combat Sarcopenia?

Despite the fact that we don’t know with certainty how to treat or prevent this condition, there is evidence that the following are helpful:

  • Participating in regular strength training and exercise: significant improvements can be seen after just 8 weeks of training 2 to 3 times per week,
  • Eating a diet with adequate protein: at least 25-30 grams of high-quality protein per meal,
  • Consuming sufficient calories,
  • Addressing Vitamin D deficiency.

Sarcopenia seems to be normal part of aging, but it can lead to weakness, disability, falls, and loss of independence in older adults. Sarcopenia can be caused by sedentary lifestyle, hormonal, neurologic and nutritional factors. The treatment of sarcopenia with resistance training can be effective, but prevention of sarcopenia through regular physical activity and nutritional strategies at an early age is an even more effective. 


DISCLAIMER: Sarah Smith MD is a medical doctor, but she is not your doctor, and she is not offering medical advice on this website. If you are in need of professional advice or medical care, you must seek out the services of your own doctor or health care professional.