Fatigue is extreme tiredness and exhaustion. It doesn’t always go away with rest or sleep and may affect you physically and emotionally. It’s a very common side effect of breast cancer treatment and may last for weeks or months after your treatment has finished.

Everyone knows what it feels like to be tired sometimes but if you have cancer-related fatigue you may feel like you have very little energy. You may find it difficult to do simple everyday tasks and it may stop you from doing things you want to do. Everyone’s experience of cancer-related fatigue is different. It’s important to know your limits and not expect too much of yourself.

It can be difficult to describe fatigue and other people may not always understand how you are feeling. It may be useful for family and friends to read this information too.

What causes cancer-related fatigue?

Breast cancer treatment

Most of the treatments used for breast cancer have side effects that can contribute to fatigue.

  • You may feel tired after surgery. This may be due to the stress placed on your body and the time it takes your body to heal.
  • The side effects of chemotherapy may include a lowered resistance to infection, anaemia (too few red blood cells in the body) and altered eating patterns. These side effects can all cause or worsen fatigue.
  • Travelling back and forth to the hospital for radiotherapy can make you feel increasingly tired and the treatment can cause fatigue because of the way it affects your body. This tiredness may start or get worse after radiotherapy has finished.
  • Hormone (endocrine) therapy and some targeted therapies may cause fatigue.

You may need to take other medicines alongside your main treatments, which can also contribute to fatigue. For example, pain relief, anti-sickness drugs, sleeping tablets and antidepressants may make you feel very tired. Steroids are often used alongside chemotherapy, which can make you feel restless and may disrupt your sleep.

Emotional effects

Many people feel worried and anxious about their diagnosis and treatment. You may find it difficult to sleep or feel depressed. These feelings and emotions may make your fatigue worse. Find out more about managing anxiety and coping with depression.

Tips for managing your fatigue

  • Tell your GP (local doctor) or nurse how you’re feeling. Your fatigue may have a treatable cause. For example, iron supplements or a blood transfusion may be prescribed for anaemia.
  • Try using a fatigue diary, where you record your level of fatigue every day from 1 (no fatigue) to 10 (extreme fatigue). This can help you think about how your treatment affects your energy levels so you can plan your day and make the most of the times when you have more energy. If you have finished treatment it can still be useful to keep a record of when you have more or less energy so you can plan any activities.
  • There is strong evidence that regular moderate exercise such as walking or swimming can help reduce fatigue.
  • Try and get plenty of rest between your daily activities, but limit the number of daytime naps you have and keep them to less than an hour at a time so that you sleep at night.
  • Use relaxation techniques to help you relax and regain energy. There are many good relaxation CDs or apps that can guide you through different techniques.
  • Drink plenty of fluids (6–8 glasses a day). Being dehydrated can make you tired.
  • Eating well can help improve your energy levels. Make the most of the times when your appetite is good and try to choose foods that give you energy over a period of time like nuts and cereals. Sugary foods may give you a quick fix but won’t keep your energy levels up for very long.
  • Try and accept offers of practical help from others where possible. Often people want to help but don’t know what you need. Let people know how they can help. 
  • There is some evidence that being well supported may help to reduce fatigue. You may like to think about joining a support group or having some individual counselling.

More tips on managing breast cancer-related fatigue.

Macmillan Cancer Support publishes an information booklet called Coping with fatigue, which you may find useful. Order it free from Macmillan's website or call 0808 808 00 00. 

Sleep disruption

Many people find it difficult to sleep when they are diagnosed with breast cancer. This may continue during treatment and for some time after treatment has ended. In most cases sleep patterns eventually return to normal.

Difficulty sleeping may be caused by a number of things.

  • Stress and anxiety – you may have concerns about the future or worries about relationships with friends and family and their expectations of you. Feeling anxious can stop you from getting to sleep, or cause you to wake in the night or wake up early.
  • Changes to your sleep pattern – your sleep pattern may have changed while you were having chemotherapy. For example, you may have started having naps during the day.
  • Changes to your daily routine – being diagnosed with breast cancer may have affected what you do each day. For example, you may have stopped working during treatment and may be getting up later, or you may have less energy and be doing less exercise.
  • Side effects of treatment – some treatments have side effects that can interfere with your sleep. For example, hormone (endocrine) therapies can cause menopausal symptoms, which can mean sleep is disrupted by night sweats or hot flushes.

When your treatment has ended you may continue to feel tired during the day. You may feel frustrated that your sleep pattern has not returned to normal immediately or guilty that you are not able to get straight back to doing the things you want to do. This is not unusual and it may take some time before your sleep pattern returns to normal.

What can I do to improve my sleep patterns?

  • Try and get some regular moderate exercise during the day, but don’t exercise late in the evening as this may disturb your sleep.
  • Try not to have drinks containing caffeine after mid-afternoon. These include tea, coffee and many fizzy drinks.
  • Limit the amount of alcohol you drink. Alcohol may help you get to sleep but it will also often wake you up in the night.
  • Limit the number of daytime naps you have and keep them to less than an hour at a time.
  • Try to go to bed and get up at the same time each day. Some people think if they have a bad night’s sleep they should go to bed early the next night, but this can make the problem worse. Think about how much sleep you get on average each night and go to bed at a time that allows you to get the sleep you need. For example, if you are sleeping for six hours a night and you get up at 6am, you should try to go to bed at midnight.
  • Do something relaxing before bedtime. For example, listen to some quiet music or an audio book, have a warm bath or practise a relaxation technique.
  • Avoid using screens (for example, watching TV or using your mobile phone) before bed.
  • Make sure your bedroom is quiet, dark and a comfortable temperature.
  • Try not to use your bedroom for other activities such as working, using your computer or watching television.
  • If you can’t get to sleep or you wake up in the night and can’t get back to sleep, try to get up rather than lying in bed. Read or listen to the radio until you start to feel tired, then go back to bed again.

What treatments are available?

Some people find it difficult to get back to their old sleeping pattern following treatment for breast cancer.

Talking therapies such as counselling or cognitive behavioural therapy (CBT) can be useful and can help you change your patterns of thinking and behaviour. If you think you might benefit from counselling or CBT, discuss these with your GP or specialist team.

Some people find yoga, meditation and relaxation techniques help them to relax and aid sleep. For more information on these, download or order our Complementary therapies booklet.

Some people may be recommended a short course of sleeping tablets to help them sleep. You can discuss this with your GP or specialist team.

You may find it helpful to listen to a short audio guide on sleeping problems from the NHS choices website.

Support for you

If fatigue or sleep disruption is having a big impact on your daily life, you don’t have to cope with this alone. You may want to join our online Forum and talk to people who are in the same situation. You can also call us free on 0808 800 6000 for information and support.

Last reviewed: November 2016
Next planned review begins shortly

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