Key points
- Most people who have chemotherapy or radiotherapy feel fatigue; this tiredness does not go away completely with rest and sleep [1].
- Exercise, cognitive behavioural therapy (CBT) and mindfulness programmes are the most effective approaches, both during and after treatment [2].
- In a review of 113 studies, medicines had no meaningful effect on fatigue [4], and the ASCO guideline does not recommend L-carnitine, antidepressants or wakefulness drugs to treat fatigue [2].
- Treatable causes such as anaemia, pain, depression, poor sleep, an underactive thyroid and poor nutrition should be checked for and treated [1, 3].
- Sudden, severe fatigue with fever, breathlessness or bleeding needs an urgent call to your doctor [1, 8].
What is cancer fatigue and why does it happen?
Cancer fatigue is different from ordinary tiredness: it can come on after little or no activity and does not go away completely with sleep and rest. People describe it as having no energy, feeling heavy, finding it hard to think and concentrate, and feeling physically and emotionally drained [1]. Fatigue can start before, during or after treatment, and for some people it lasts for months or years after treatment [1].
It usually has several causes [1, 6]:
- The cancer itself: cancer cells use energy, and the body releases substances called cytokines that cause tiredness in large amounts. Inflammation is one of the main mechanisms of fatigue [1, 6].
- Treatment: surgery, chemotherapy, radiotherapy, hormone therapy, immunotherapy and targeted therapy can all cause fatigue. With radiotherapy, fatigue usually builds up until halfway through the course and then stays the same until the end of treatment [1].
- Side effects of treatment: anaemia, poor appetite, diarrhoea and vomiting (dehydration), hot flushes and night sweats, infection, pain and poor sleep [1].
- Emotional factors: anxiety, worry and depression [1].
What helps?
Practical steps for managing fatigue
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Keep moving, even a little
Exercise (including walking) is one of the most effective ways to reduce fatigue [2, 4]. The evidence shows that moderate aerobic exercise (such as brisk walking or cycling) about three times a week, on its own or with strength training, reduces fatigue; the most important message is "avoid inactivity" [5]. Choose an activity you enjoy so you can keep it up [1], and work out a plan that suits you with your doctor or a physiotherapist.
- 2
Manage your energy
Do the most important things at the times of day when you have the most energy, and limit the things that tire you out. Hand heavy jobs such as shopping, cooking and driving to family and friends [1].
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Mind and body
Tai chi and qigong during treatment, and yoga after treatment ends, have helped reduce fatigue [2].
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Eat well and drink enough
Ask a dietitian about foods that keep your energy up. Try small, frequent meals, drink enough fluids and limit caffeine and alcohol [1].
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Keep a fatigue diary
Write down your energy level every day. This helps your doctor see the pattern of your fatigue and its possible causes [1].
An international expert consensus concluded that exercise and exercise testing are safe for most cancer survivors and can improve fatigue, anxiety, depression, physical function and quality of life [5]. If you have bone metastases, very low platelets or white blood cells, or a heart problem, talk to your doctor before you start.
What can your doctor do?
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Your care team first looks for treatable causes: an examination and blood tests to check for anaemia or infection, and an assessment of pain, sleep, mood and nutrition [1, 3]. Then [1, 2]:
- Treating anaemia with changes to diet, medicines or a blood transfusion, depending on the cause.
- Controlling pain and adjusting painkillers, because some painkillers cause tiredness themselves.
- Treating anxiety and depression, especially with cognitive behavioural therapy.
- Referral to physiotherapy or a supervised exercise programme.
- American ginseng may be suggested during treatment [2]. Talk to your doctor before taking any supplement, because it may interact with your medicines.
For physicians
Guideline summary for physicians
- ASCO–SIO 2024 (113 randomised trials): during treatment, exercise, CBT, mindfulness-based programmes and tai chi or qigong are recommended; psychoeducation and American ginseng may be recommended. After treatment, exercise, CBT and mindfulness (especially for moderate to severe fatigue) are recommended, and yoga, acupressure and moxibustion may be recommended. At the end of life, CBT and corticosteroids can be offered. L-carnitine, antidepressants and wakefulness agents should not be recommended, and psychostimulants are not routinely recommended either. The certainty of evidence is low to moderate [2].
- ESMO 2020: regular screening for fatigue in all patients, and assessment and treatment of modifiable contributing factors (anaemia, pain, emotional distress, sleep disturbance, endocrine and nutritional disorders) before specific interventions [3].
- American ginseng (double-blind trial N07C2): 2000 mg daily for 8 weeks reduced fatigue more than placebo, with no difference in side effects [7].
- Mustian meta-analysis: weighted effect size 0.30 for exercise, 0.27 for psychological interventions, 0.26 for combined exercise and psychotherapy and 0.09 for drugs (P=0.05; not significant) [4].
Myths and facts
| Common belief | Fact |
|---|---|
| When I am tired I should rest as much as I can. | Too much rest and inactivity can make fatigue worse; suitable exercise is one of the most effective treatments [4, 5]. |
| Fatigue is an unavoidable part of cancer and nothing can be done. | Treatable causes (anaemia, pain, depression, poor sleep) should be checked, and exercise, CBT and mindfulness have proven effects [2, 3]. |
| Fatigue after treatment ends means the cancer has come back. | Fatigue can go on for months or years after treatment [1]; even so, tell your doctor about any new change. |
When should I call my doctor?
- A temperature of 38 °C or higher, shivering or signs of infection during chemotherapy; this is an emergency [8].
- Breathlessness, a racing heart, chest pain, dizziness or fainting; this may be a sign of severe anaemia or another problem [1].
- Fatigue that suddenly gets much worse, or you can no longer manage everyday tasks (washing, eating, walking) [1].
- Feeling hopeless, constantly sad or losing interest in everything; depression can be treated [1].
Frequently asked questions
How long does fatigue last after treatment ends?
Is coffee good for fatigue?
The NCI advises limiting caffeine [1], because a lot of caffeine, especially in the evening, can disturb your night's sleep and make the next day's fatigue worse.
Is there a specific medicine for cancer fatigue?
There is no standard medicine for cancer fatigue [1]. ASCO does not recommend routine use of psychostimulants, antidepressants (for fatigue) or wakefulness drugs, and did not find L-carnitine or other supplements effective, except American ginseng during treatment [2]; at the end of life, corticosteroids may be suggested [2].
References
8 referencesShow all references, 6 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
- 1
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- 5
- 6Cancer-related fatigue—mechanisms, risk factors, and treatments
- 7Wisconsin Ginseng (Panax quinquefolius) to Improve Cancer-Related Fatigue: A Randomized, Double-Blind Trial, N07C2
- 8
This page is based on reputable scientific sources and was last updated on 28 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
Printed from the website; the full and up-to-date version: https://drdabiri.com/en/guides/fatigue/