5 Min Read
Last Updated: 05/29/2024
Fact Checked

Written by Karen Selby, RN | Medically Reviewed By Dr. Jeffrey Velotta | Edited By Walter Pacheco

What Is Muscle Weakness?

Muscle weakness is a loss of muscle strength when standard effort doesn’t produce a full contraction or movement with flexing. Muscle weakness can make it hard for patients to lift things or walk. Cancer-related muscle weakness is a common mesothelioma symptom.

Most mesothelioma patients already have muscle loss because of aging or conditions such as diabetes. These can mask muscle weakness as a sign of cancer. Muscle weakness can also worsen as cancer spreads throughout the body.

Muscle Atrophy, Muscle Loss and Muscle Weakness

Muscle weakness can involve underlying disease. These include mesothelioma and non-illness causes such as poor physical conditioning or malnutrition. In these cases, muscles may not contract or move as quickly as before, or you may get more tired with muscle use.

The terms muscle atrophy, wasting, thinning and loss are often used interchangeably. After periods of muscle disuse, muscles will become smaller because of tissue loss and muscle mass loss. Mesothelioma or neurologic diseases can prevent muscle use. This causes muscle weakness and muscle atrophy.

What Causes Muscle Weakness?

Muscle weakness has many causes, including disease, malnutrition, chemical imbalance or lack of exercise. In mesothelioma patients, cancer can cause metabolic changes that prevent muscles from getting the necessary nutrients. Mesothelioma patients can take specific steps to prevent muscle weakness, such as regular exercise and increased dietary protein. However, muscle weakness typically becomes severe when mesothelioma reaches stage 4.


Chemotherapy often causes side effects such as mouth sores and nausea, making eating difficult. A balanced diet is essential for mesothelioma patients undergoing or recovering from any treatment.

Getting plenty of protein is particularly important for minimizing muscle weakness. When the body does not get enough protein from food, it uses muscle protein. Cancer and cancer treatment can also cause nausea and lack of appetite. This makes it more challenging to avoid malnutrition.

As they grow, solid tumors in mesothelioma and lung cancer consume calories and protein, leaving fewer nutrients for muscles. In addition, cancer treatment can also cause anemia. This condition involves low red blood cell counts, making it harder for the blood to carry nutrients to muscles throughout the body.

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Lack of Oxygen

Breathing difficulties can cause a lack of oxygen. Muscles use oxygen to break down glucose and produce energy. Without enough oxygen, abnormal breathing can cause asphyxiation. It can also cause a state of generalized hypoxia that can lead to unconsciousness or death. Mesothelioma can make breathing tough. This makes it more challenging for your body to supply muscles with enough oxygen. Chronic respiratory illnesses can decreased oxygen levels, reducing muscle mass over time.

Fatigue and Inactivity

In a 2021 clinical research study of predominantly male epithelioid mesothelioma patients with an average age of about 72 years, 81% of patients reported regular fatigue. Cancer-related fatigue affects everyone differently. A patient may feel energetic one day but not have enough energy to get out of bed the next.

Mesothelioma tumors use up energy as they grow. This leaves fewer resources for the rest of the patient’s body. Reduced oxygen and difficulty breathing with pleural mesothelioma can lead to fatigue. Palliative treatment for cancer pain is an important part of minimizing fatigue.

Treatments, such as chemotherapy and radiation, can also cause fatigue. These treatments kill cancer cells along with healthy cells. The body then has to use energy to heal tissues. Treatments may also reduce red blood cells, causing anemia-related fatigue.

Exercise for mesothelioma patients can help maintain healthy muscle mass. But patients should consult their doctors before starting a workout regimen. Eating a nutrient rich mesothelioma diet can prevent fatigue from poor nutrition.

How Does Mesothelioma Cause Muscle Weakness?

Mesothelioma causes chemical imbalances in the body that interfere with muscle function. This can lead to muscle weakness. Cancer can spread and metastasize into muscle tissue or other sensitive tissues. Muscle weakness can also be a side effect of supportive medications such as glucocorticoids.

If mesothelioma spreads to organs such as the adrenal glands, it may cause a hormone imbalance in the body. If cancer spreads into bones, the bones will release calcium and other chemicals harmful to muscles at high levels. If cancer spreads into the spinal cord, it may make it harder for signals from the brain to reach muscles lower in the body.

Tumors and cancer treatments can also cause inflammation, leading to a high level of pro-inflammatory cytokines in the body. These chemicals reduce muscle function and growth. Surgery patients require extra protein and calories for healing, and radiation side effects, such as fatigue and esophagitis, can cause difficulties with swallowing.

Treating Mesothelioma-Related Muscle Weakness

Treating mesothelioma-related muscle weakness involves identifying and managing the underlying cause. Malnutrition can be improved with diet or appetite stimulants, and patients with low activity can work with their doctor to develop an exercise plan. Cachexia is a “wasting” disorder seen in the later stages of cancer that involves severe weight and muscle loss. If caught early, interventions such as high-calorie diets and nutrient-dense supplements can limit the effects of cachexia. A healthy, balanced diet is one of the most efficient ways to prevent or treat mesothelioma-related muscle weakness.

Talking to your doctor about symptoms during mesothelioma treatment is essential because they can affect your nutrition or ability to exercise. Palliative treatments such as thoracentesis can reduce pressure in the chest and improve breathing. Improved symptoms can reduce fatigue and limit muscle weakness, leading to a better quality of life.

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