For some people with cancer, chemotherapy can be an important treatment option. But as with other forms of cancer treatment, chemotherapy can sometimes come with unwanted side effects, such as fatigue. Fatigue is the most common side effect of cancer treatments, including chemotherapy.

According to the National Cancer Institute (NCI), fatigue is the most common side effect of many cancer treatments. It is also different from the fatigue that those without cancer experience.

This article will focus on the relationship between chemotherapy and fatigue. It will look at signs of fatigue during chemotherapy, how long this fatigue can last, and whether the fatigue worsens as treatment goes on.

This article will also look at treatment options and care tips for fatigue during chemotherapy.

A person wearing a blue shirt who may be experiencing chemotherapy-related fatigue.Share on Pinterest
Willowpix/Getty Images

As a 2020 review explains, chemotherapy is a type of cancer therapy. An individual undergoing chemotherapy uses medications that function to help prevent the growth and multiplication of cancer cells.

Some people use the term “chemo fatigue” for the fatigued state that certain individuals experience when undergoing chemotherapy.

The NCI note that when someone is fatigued, they tend to:

  • feel tired, heavy, weak, worn out, or sluggish
  • lack energy
  • struggle to find the motivation to do things

The term chemo fatigue is not widely used in medical or scientific circles. But doctors are well aware of the link between chemotherapy and fatigue, as well as the link between cancer and fatigue more broadly. For example, people with cancer get fatigued more easily than people without cancer.

As the NCI states, it is unclear how cancer treatments such as chemotherapy can cause fatigue. They note that by the time cancer treatment begins, those with cancer are likely already tired from tests, surgery, and emotional stress. Treatment may worsen the feelings of fatigue.

Different cancer treatments can affect a person’s energy levels.

Some chemotherapy types can stop the bone marrow from creating new red blood cells, which results in anemia. Anemia can affect a person’s energy level.

In addition, chemotherapy can cause a person to have a low appetite. When a person does not consume enough food, the body is unable to create enough energy, which can contribute to feelings of fatigue.

The American Cancer Society (ACS) provides additional explanations for why chemotherapy causes fatigue. For example, because cancer treatment options kill cancerous and noncancerous cells, the body must use more energy to remove the resultant cell waste and to repair damaged tissues. This may cause fatigue.

When someone’s fatigue occurs due to chemotherapy, certain things can make the fatigue worse. These include:

When someone is receiving chemotherapy for cancer, some of the fatigue may occur due to the cancer itself, and not the chemotherapy. Cancer causes fatigue through some of the health problems that it can bring about. These include:

  • dehydration
  • infection
  • stress
  • losses in muscle or strength
  • changes in hormone levels

Fatigue is different from tiredness. To tell them apart, the ACS provides the following list of signs of fatigue:

  • a feeling of tiredness that does not ease with rest or sleep
  • tiredness that does not seem to be caused by any particular activity
  • tiredness that interferes with a person’s work or social life
  • typical activities feeling more tiring than usual, perhaps to the extent that these activities feel impossible
  • legs and arms feel heavy and difficult to move
  • feelings of weakness and lack of energy
  • spending more time in bed than usual, perhaps more than 24 hours
  • sleeping more or less than usual
  • confusion and difficulty concentrating

An individual undergoing chemotherapy can use this list to help them determine whether they have fatigue and the extent of their fatigue.

According to a 2015 article, fatigue is a very common symptom of cancer and side effect of cancer medication. Between 30%–60% of people with cancer will experience fatigue during treatment, and treatment can worsen preexisting fatigue.

For certain individuals, this side effect can last for a long time. Some people experience fatigue for months or years after their successful cancer treatment. Between 25%–33% of those who previously had cancer report feeling fatigued up to 10 years after receiving a cancer diagnosis.

The intensity of a person’s chemo fatigue also varies with time. Doctors often administer chemotherapy drugs in stages. As the NCI explains, someone’s chemo fatigue will tend to be worst just after having received a stage of medication. After a few days, the fatigue should begin to decrease.

A person’s chemo fatigue does not necessarily get worse with each stage or round of chemotherapy.

As the NCI notes, some evidence suggests that people’s chemo fatigue is usually worst during the middle of their chemotherapy treatment.

This means that someone could receive several rounds of chemotherapy after that, with each round reducing the intensity of their fatigue.

The NCI also provides some helpful information about the typical treatment options for cancer-related fatigue.

Doctors often treat the condition that is causing or worsening the fatigue. This could be pain, depression, or anemia.

For instance, if the cause is anemia, then doctors could recommend:

  • dietary changes
  • a red blood cell transfusion
  • medications to promote red blood cell growth

Doctors may also recommend treating cancer-related fatigue directly. This could involve psychological treatments such as cognitive behavioral therapy, or even increases in exercise.

Additionally, scientists are currently looking into medications and dietary supplements for cancer-related fatigue. These include:

According to a 2014 article, although the literature on mind-body interventions is small, people may find it beneficial to take part in:

Aside from the above treatment options, some strategies may help individuals to manage their chemotherapy-related fatigue.

The NCI suggests working with the healthcare team to do the following:

  • Eat a balanced diet.
  • Learn how rest and activity affect the fatigue.
  • Identify things that help to decrease the fatigue.
  • Schedule important activities for periods of lower fatigue.
  • Find activities that improve alertness without being tiring, such as bird watching or walking in a park.
  • Learn to distinguish between fatigue and depression.

If a person notices that they are having problems with their nerves or muscle weakness, they should ask a healthcare professional if they require physical therapy.

Respiratory therapy may be beneficial if a person notices that they are having trouble breathing.

Tips for changes in taste and appetite

Chemotherapy can lead to changes in a person’s appetite and taste, which can result in low energy levels and fatigue.

To help combat the changes in appetite, a person can try the following:

  • eating several small meals and snacks each, day as this can be easier to manage
  • asking a doctor for high-calorie drinks to sip between chemotherapy treatments
  • when a person feels able to eat, trying to eat high-calorie foods

It is important to remember to drink plenty of fluids if a person feels unable to eat. But try not to fill up the stomach with liquid before a meal.

If a person’s taste has changed, they can try the following:

  • avoiding foods that taste strange, but trying them every few weeks or so
  • choosing foods with strong flavors if a person finds that their food tastes the same
  • avoiding hot and spicy foods if mouth ulcers are present
  • using plastic utensils if metal ones taste strong

A person may prefer eating tart foods that have a strong taste, such as citrus.

Many people who use chemotherapy will feel fatigued at some point during their treatment. Those undergoing chemotherapy can feel fatigued as a result of the cancer itself or the chemotherapy treatment.

Contributing factors for fatigue include pain, depression, anxiety, lack of sleep, and other medications a person takes while undergoing chemotherapy.

Some chemotherapy drugs can lead to anemia, which can affect a person’s energy levels.

Fatigue is a common side effect of chemotherapy, and it is important that a person speaks with a healthcare professional to receive treatment.

Treatment can include dietary and lifestyle changes alongside medications, therapy, and for some, yoga and mindfulness.