Cancer Fatigue

Cancer Fatigue

When you get a good night’s sleep after a busy day, you usually feel refreshed and less tired the next day. With cancer fatigue, you feel tired all the time — sleeping more doesn’t help.

Cancer fatigue can make you feel tired, weak, listless, exhausted, or like you have no energy. You may feel like your arms and legs are heavy and sluggish. You may have little desire to do anything and find it too tiring to eat or even walk to the mailbox, let alone go to work or school.

Also called cancer-related fatigue by doctors, cancer fatigue is the most common side effect of cancer treatment. According to the American Cancer Society, between 80% and 100% of people diagnosed with cancer report having fatigue.

When you get a good night’s sleep after a busy day, you usually feel refreshed and less tired the next day. With cancer fatigue, you feel tired all the time — sleeping more doesn’t help.

Cancer fatigue can dramatically affect your quality of life by making you feel too exhausted to participate in your usual activities and social events. In many cases, physical fatigue can lead to mental fatigue and mood changes.


What causes cancer fatigue?

There are a number of things that can cause cancer fatigue.

Breast cancer. Breast cancer causes changes in your body that can lead to fatigue. Many breast cancers release proteins called cytokines, which have been linked to fatigue. Breast cancer also may change your body’s hormone levels and cause inflammation, both of which may contribute to fatigue.

Breast cancer treatment. Surgery, radiation therapy, chemotherapy, hormonal therapy, targeted therapy, and immunotherapy all may cause fatigue. Many medicines used to treat breast cancer affect both healthy cells and cancer cells. You may feel fatigue as your body works to repair or replace damaged healthy cells.

Treatment side effects. A number of side effects are also linked to fatigue, including pain, nausea, low red blood cell counts (anemia), low white blood cell counts, diarrhea, dehydration, trouble sleeping, and vomiting.

Your emotional health. People diagnosed with breast cancer often report feeling stressed, anxious, or depressed. All these emotions can lead to fatigue.

Poor nutrition. If you’ve been diagnosed with breast cancer, you may need more or different nutrients than usual. But it can be hard to stick to a healthy diet and eat enough if treatment makes you feel sick or throw up.

Pain medicines. A number of pain medicines, such as codeine and morphine, are known to cause fatigue.

Lack of exercise. It may sound counterintuitive, but exercising, even gentle walking, can give you more energy. Not exercising can make you feel sluggish and tired.


Cancer fatigue symptoms

People describe cancer fatigue in many different ways. Common symptoms include:

  • feeling a lack of energy

  • sleeping less

  • sleeping more, but still feeling tired

  • having no interest in your normal activities

  • having trouble thinking or concentrating

  • feeling sad all the time

  • paying less attention to your personal appearance

  • feeling so tired you can’t do even small tasks, like use the television remote or make a phone call

  • feeling nervous or anxious

  • feeling very weak


How long does cancer fatigue last?

Unfortunately, if you have cancer fatigue, there is no way to know how long it might last or how severe it might be. Fatigue from breast cancer and breast cancer treatment can last for weeks, months, or years and may continue after you finish treatment.

It’s important to know that the effects of cancer fatigue can change from day to day. If you’re receiving chemotherapy, targeted therapy, or immunotherapy in cycles, the fatigue is often worse at the beginning of the cycle and then eases until the next cycle starts. If you’re receiving radiation therapy, fatigue usually gets worse as treatment goes on and then eases a few months after you finish treatment.


Managing cancer fatigue

If you think you have cancer fatigue, the first thing to do is to talk with your doctor. Many people think that fatigue is just part of cancer treatment, and so they don’t mention it. Although fatigue is common, it is a side effect that can be treated and managed.

Usually, there is no single cause of cancer fatigue. So your doctor may add nurses, social workers, physical therapists, pharmacists, and registered dietitians to your care team to help you manage its symptoms.

It can help your care team develop strategies to ease fatigue if you keep a journal or log that includes:

  • all your breast cancer-related symptoms and treatment side effects

  • when the symptoms and side effects started

  • how severe the symptoms and side effects are throughout each day

  • how you’re feeling physically and emotionally each day

Treating specific side effects, such as pain or anemia, can help ease cancer fatigue, but your doctor is likely to recommend other activities and therapies that can help manage fatigue symptoms. Recommendations may include:

Some people find the following strategies to help ease fatigue helpful:

  • Take short naps and breaks, aiming for no more than 30 minutes. If you sleep or rest for longer than 30 minutes, you may likely have trouble sleeping at night.

  • Try to sleep seven to eight hours each night. It’s also a good idea to try to go to sleep and wake up at the same time each day.

  • Take a walk every day.

  • Ask your family or friends to help with things you find too tiring to do, like yard work or grocery shopping.

  • Avoid caffeine.

  • Drink enough water. If you have diarrhea or are throwing up because of treatment, you may need to drink more than eight glasses a day. Ask your doctor how much water is best for your unique situation.

  • Plan your day so you can do activities when you have the most energy, and schedule rest periods when you know your energy is low. For example, if you find you have the most energy right after you get up in the morning, it may be the best time to exercise or go for a walk.

Written by: Jamie DePolo, senior editor

— Last updated on September 20, 2022, 12:42 AM


Reviewed by 1 medical adviser
Brian Wojciechowski, MD
Crozer Health System, Philadelphia area, PA
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