Cancer-related fatigue

This information explains cancer-related fatigue, its causes and some ideas for managing it.

What is the difference between fatigue and tiredness?

Fatigue is often confused with tiredness. Tiredness happens to everyone – it is an expected feeling after activity or at the end of the day. Usually, you know why you are tired and a good night’s sleep solves the problem. Fatigue is overwhelming tiredness (physical and emotional) not relieved by rest or sleep.

What is cancer-related fatigue?

Cancer-related fatigue is one of the most common side effects of cancer and its treatment. It can happen to anyone, with any type of cancer, at any time during or after treatment. Fatigue can happen even if you haven’t been exercising.

For patients and carers, the fatigue associated with cancer treatments can be overwhelming. The symptoms can range from mild to severe and be so disruptive they make daily activities hard to do. 

The reason for this fatigue is often unknown, but it is thought to have a combination of causes. These could include:

  • the cancer itself
  • waste products of dead cancer cells
  • treatment side effects
  • lack of sleep or appetite
  • higher levels of cytokines (proteins) in the blood
  • effects on endocrine glands, like the thyroid.

Cancer treatments and fatigue

  • Chemotherapy – Any chemotherapy drug may cause fatigue, but it may be more common with vincristine, vinblastine and cisplatin. People often experience fatigue after several weeks of chemotherapy, and fatigue can continue for several months after chemotherapy has been completed.
  • Radiation treatment – This can cause fatigue that increases over time. Fatigue usually lasts three to four weeks after treatment stops but can continue for several months.
  • Bone marrow transplant – This form of treatment can cause long-term fatigue.
  • Hormonal therapies This can cause lack of energy and tiredness.
  • Biological therapy – This can lead to ongoing fatigue.
  • Combination therapy – More than one cancer treatment at the same time or one after the other increases the chances of developing fatigue.
  • Side effects of treatments – Side effects such as nausea, vomiting, mouth ulcers, taste changes, heartburn or diarrhoea can add to fatigue.

Other things that may add to cancer-related fatigue

  • Infection – Chemotherapy can weaken your body’s immune system (your body’s ability to fight off infections). Fatigue may be one of the first signs of an infection; especially if fatigue comes on quickly. You should check your temperature if you feel unwell while on chemotherapy, and contact the hospital cancer services immediately if you think you could have an infection.
  • Anaemia – Anaemia is when there is not enough haemoglobin (a substance in red blood cells that carries oxygen around the body) in your blood. Anaemia can cause fatigue but it is treatable.
  • Low levels of thyroid hormones (Hypothyroidism) – This can occur after radiation treatment to the lymph glands in the neck, including the thyroid gland. It can be treated with medication.
  • Medications – Some medications used to treat side effects (such as nausea, pain, depression, anxiety and seizures) can cause fatigue, as can some medications for other conditions you might have.
  • Pain – Dealing with pain can make you feel very tired, so managing your pain can help.
  • Stress/Anxiety – Stress and anxiety can increase fatigue levels. You may find counselling or relaxation exercises useful. Cancer Society has two free Relaxation CDs available on our website.
  • Depression – Depression and fatigue sometimes go together. If your mood is low, and you have lost interest in things you used to enjoy, you may benefit from treatment for depression.
  • Interrupted sleep –Interrupted sleep can occur due to pain, being in hospital, worry and nausea.

What can I do about fatigue?

  1. Consider your energy level. Think of your personal energy stores as a “bank”. Over the day/week you make regular deposits to keep yourself energised (by eating nutritious food and resting), as well as withdrawals (through moderate exercise, household chores and going to treatment). You may find it helpful to keep a diary or notes about how you are feeling, and you may see a pattern in your levels of energy and fatigue.
  2. Be aware of your own warning signs of fatigue; for example short temper, loss of appetite or low mood.
  3. Help others understand and support you. Talk to family and friends about how they can help. Be specific, for example: “I need someone to do the vacuuming every week”.

You can do many things in your everyday life that will help you to save your energy. Taking short cuts on some things or getting help from other people may help.

You could:

  • Plan ahead and give yourself plenty of time to get to places.
  • Pace yourself. Combine activities and try to spread the load evenly during the week rather than doing everything at once.
  • After your shower or bath, sit down to dry off.
  • Get dressed sitting down. Prepare your clothes and lay them out in one place before you dress.
  • Where possible, do household tasks sitting down; for example peeling vegetables or ironing.
  • If you have children, play games that you can do sitting or lying down; for example reading, puzzles, board games or drawing.
  • Write a shopping list and go when the shops are quiet.
  • Ask family and friends for help with shopping, housework or collecting the children from school. Accept offers of practical help.
  • Have plenty of nutritious snacks and drinks in the house so you can have something quickly and easily whenever you feel like eating.
  • Don’t forget to do things that you enjoy. It may help distract you from your cancer and make you feel more relaxed. Learning relaxation techniques including deep breathing or visualisation may be helpful. Find activities that divert your attention away from fatigue, such as knitting, reading, music, or having a massage.
  • It can help to have a “power nap” for an hour or less during the day. Try to have your nap early in the afternoon so your night sleep is unaffected. Alternate periods of activity and rest.
  • Use Facebook, an answerphone and emails to update friends and family on how you are rather than seeing lots of visitors.


  • Cancer-related fatigue is often made worse if you are not eating enough or not eating the right foods. Eat as well as you can. There is good advice in the Cancer Society booklet Eating Well During Cancer Treatment/Kia Pai Te Kai I Te Wā Maimoatanga Matepukupuku. To read the booklet, visit our website or phone the Cancer Society Helpline 0800 CANCER (226 237) to receive a copy.
  • Ideally you should stay about the same weight you were before you had cancer – if you are struggling to do this, it may be useful to see a dietitian.
  • Try to eat a wide variety of healthy foods, including protein.
  • Make sure you drink plenty if you can. Aim to drink eight cups of fluid every day. Fluids could include water, juice, milk, soup and milkshakes. You will need more fluid if you have side effects such as vomiting and diarrhoea.


  • There is evidence that exercise helps reduce cancer-related fatigue. Regular moderate exercise can lessen feelings of tiredness and a lack of energy. During cancer treatment it is often possible to continue exercising.
  • Talk to your doctor before beginning an exercise programme.
  • Start slowly, allowing your body time to adjust.
  • Most exercises are safe as long as you exercise with care and don’t overdo it.
  • Good exercise activities include walking, and cycling.
  • Some gyms have specialised programmes.


  • Tell your medical team how much fatigue you have and how much it is affecting you. Don’t just assume there is nothing that could help and that you just have to put up with it.
  • Talk to a cancer nurse or counsellor.
  • Connect with others going through the same thing, such as CancerConnect.
  • Join an online support group or chat room, such as CancerChatNZ.
  • Talk with your religious or spiritual advisor.

Cancer-related fatigue usually begins to lift when treatment ends, but some people are fatigued for some time after treatment is finished. Fatigue can go away only to return again. You may be frustrated if your recovery takes longer than you expected. Try to be patient with yourself.

Recommended readings and websites

Macmillan Cancer Support 

Living well beyond breast cancer by Dr Marisa Weiss and Ellen Weiss, Three Rivers Press, United States of America, 2010.

Before and after cancer treatment by Dr Julie K. Silver, John Hopkins University Press, United States of America, 2015.

Surviving after cancer: living the new normal by Dr Anne Katz, Rowman & Littlefield Publishers, United States of America, 2011.

This information was reviewed in 2016 by the Cancer Society of New Zealand. The Cancer Society’s information is reviewed every three years.