Muscle atrophy is when muscles appear smaller than usual due to a lack of muscle tissue. Low physical activity, nutritional deficiencies, genetic factors, and some medical conditions may contribute.

Muscle atrophy can occur after long periods of inactivity. If a muscle does not get any use, the body will eventually break it down to conserve energy.

Muscle atrophy that develops due to inactivity can occur if a person remains immobile while they recover from an illness or injury. Getting regular exercise and trying physical therapy may reverse this form of muscle atrophy.

People can treat muscle atrophy by making certain lifestyle changes, trying physical therapy, or undergoing surgery.

In this article, we look at some other causes, symptoms, and treatments of muscle atrophy.

Many factors can cause muscle atrophy, including:

Poor nutrition

Muscle atrophy and wasting in legs.Share on Pinterest
Muscle atrophy has numerous potential causes.

Poor nutrition can give rise to numerous health conditions, including muscle atrophy.

Specifically, the International Osteoporosis Foundation warn that diets low in lean protein, fruits, and vegetables can lead to reductions in muscle mass.

Malnutrition-related muscle atrophy may develop as a result of medical conditions that impair the body’s ability to absorb nutrients, such as:

Cachexia is a complex metabolic condition that causes extreme weight loss and muscle atrophy. Cachexia can develop as a symptom of another underlying condition, such as cancer, HIV, or multiple sclerosis (MS).

People who have cachexia may experience a significant loss of appetite or unintentional weight loss despite consuming a large number of calories.


As a person gets older, their body produces fewer proteins that promote muscle growth. This reduction of available protein causes the muscle cells to shrink, resulting in a condition called sarcopenia.

According to a Food and Drug Administration (FDA) report, sarcopenia affects up to a third of people ages 60 and above.

In addition to reduced muscle mass, sarcopenia can cause the following symptoms:

  • weakness or frailty
  • poor balance
  • difficulty moving
  • lower endurance

A loss of muscle mass may be an inevitable result of the natural aging process. However, it can increase the risk of injuries and negatively impact a person’s overall quality of life.


Spinal muscular atrophy (SMA) is a genetic disorder that causes a loss of motor nerve cells and muscle atrophy.

There are several different types of SMA that fall into the following categories:

  • SMA linked to chromosome 5: These types of SMA occur due to a mutation in the SMN1 genes on chromosome 5. The mutations lead to a deficiency of the survival motor neuron protein. SMA typically develops in childhood but can develop at any point in life.
  • SMA not linked to chromosome 5

Muscular dystrophy refers to a group of progressive conditions that cause loss of muscle mass and weakness.

Muscular dystrophy occurs when one of the genes involved in protein production mutates. A person can inherit genetic mutations, but many occur naturally as the embryo develops.

Medical conditions

Illustration of muscle atrophy. Image credit: OpenStax, 2016.Share on Pinterest
Atrophied muscles are smaller than healthy muscles.
Image credit: OpenStax, 2016.

Diseases and chronic conditions that can contribute to muscle atrophy include:

  • Amyotrophic lateral sclerosis (ALS): Also called Lou Gehrig’s disease, ALS includes several types that damage the motor nerve cells that control the muscles.
  • MS: This chronic condition occurs when the body’s immune system attacks the central nervous system, causing harmful inflammation in the nerve fibers.
  • Arthritis: Arthritis refers to inflammation of the joints that causes pain and stiffness. Arthritis can severely limit a person’s mobility, which could lead to muscle disuse and atrophy.
  • Myositis: The term myositis refers to inflammation of the muscles. This condition causes muscle weakness and pain. People can develop myositis after a viral infection or as a side effect of an autoimmune condition.
  • Polio: This infectious disease attacks the nervous system. It causes flu-like symptoms and can result in permanent paralysis.

Neurological problems

An injury or condition can damage the nerves that control the muscles, resulting in a condition called neurogenic muscle atrophy.

When this develops, the muscles stop contracting because they no longer receive signals from the nerve.

The symptoms of muscle atrophy vary widely depending on the cause and severity of muscle loss.

In addition to reduced muscle mass, symptoms of muscle atrophy include:

  • having one arm or leg that is noticeably smaller than the others
  • experiencing weakness in one limb or generally
  • having difficulty balancing
  • remaining inactive for an extended period

Treatments for muscle atrophy vary depending on the degree of muscle loss and the presence of any underlying medical conditions.

Treating the underlying condition causing the muscle atrophy may help slow down the progression of the muscle loss.

Treatments for muscle atrophy include:

Physical therapy

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Physical therapy may help improve mobility in people with muscle atrophy.

Physical therapy involves performing specific stretches and exercises with the aim of preventing immobility. Physical therapy offers the following benefits to people who have muscle atrophy:

  • preventing immobility
  • increasing muscle strength
  • improving circulation
  • reducing spasticity, which causes continuous muscle contraction

Functional electric stimulation

Functional electrical stimulation (FES) is another effective treatment for muscle atrophy. It involves the use of electrical impulses to stimulate muscle contraction in affected muscles.

During FES, a trained technician attaches electrodes to an atrophied limb. The electrodes transmit an electrical current, which triggers movement in the limb.

Focused ultrasound therapy

This technique delivers beams of ultrasound energy to specific areas in the body. The beams stimulate contractions in atrophied muscle tissue.

This novel technology is in the development phase and has not yet entered the clinical trial phase.


Surgical procedures may improve muscle function in people whose muscle atrophy is related to neurological conditions, injuries, or malnutrition.

Muscle atrophy, or muscle wasting, is characterized by a significant shortening of the muscle fibers and a loss of overall muscle mass.

Several factors can contribute to muscle atrophy, such as:

  • remaining immobile for long periods due to illness or injury
  • age
  • malnutrition
  • genetics
  • neurological problems
  • certain medical conditions, such as arthritis, myositis, ALS, and MS

Treatment options will depend on each individual case, but they may include physical therapy, nutritional intervention, or surgery.