Information alert

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  • Cancer-related fatigue affects nine out of 10 people diagnosed with cancer. 
  • It is not the same as tiredness. 
  • Tiredness is a normal feeling which goes after sleep or rest. 
  • Cancer-related fatigue often leaves you feeling unrefreshed after sleep. 
  • It can affect your physical, mental, emotional, social and financial wellbeing. 

  • Feelings of having no energy 
  • Wanting to spend longer in bed than normal 
  • Difficulty completing tasks that were once easy to do 
  • Trouble concentrating or making decisions 
  • Problems with memory or thinking skills 
  • A ‘fuzzy’ head 
  • Difficulty breathing after only a short walk 
  • Feeling tearful or depressed 
  • Weakness of muscles 
  • Heavy limbs. 

Fatigue can affect people in different ways and at different times. It’s normal to feel fatigue during treatment and this can continue for a while after your treatment finishes. 

For most, their energy will return to normal within six to 12 months of finishing treatment. Some people may have fatigue for longer than that. 

Cancer-related fatigue may be caused by: 

  • The cancer itself 
  • Cancer treatments 
  • Side effects of cancer treatments, such as hot flushes or anaemia 
  • Nutritional problems (for example not being able to eat due to nausea, mouth ulcers, vomiting or diarrhoea) 
  • Emotional distress (feeling any emotion quite strongly can cause emotional distress) 
  • Pain 
  • Poor sleep 
  • Being less active 
  • Medicines 
  • Other health problems, such as diabetes or thyroid problems.

Try to be active

We now know that being physically active during and after cancer treatment can aid your recovery and improve your energy levels. You should aim to:  

  • Do 30 mins of exercise a day, five days a week  
  • Start with what you can do and build up 
  • Choose an activity that: 
    • you enjoy 
    • raises your heartbeat 
  • Spend less time sitting 
  • Choose options that are more active (such as taking the stairs). 


Resting gives your body a chance to recharge. Resting is more helpful before you get extreme fatigue rather than afterwards. So, try to pause and rest before you get too tired. You can stay awake to rest – just stop what you’re doing and sit, or lie down, for a while. 

You can take short naps during the day if you need to. But remember that napping may affect your sleep at night, so try to keep naps to 30 minutes or less. 

Improve your sleep

Here are some tips if you struggle to sleep:  

  • Wake up at the same time each day. 
  • Avoid lie-ins.  
  • Stay active during the day. 
  • Keep naps to 30 minutes. 
  • Avoid caffeine, alcohol or sugar in the evening. 
  • Do something relaxing before bed, such as a relaxation technique. 
  • Make sure your bedroom is dark and quiet. 
  • Write your worries down. 
  • Get out of bed if you have been trying to sleep for more than 30 minutes. 

Eat a healthy diet

Eating a healthy diet is one of the best choices you can make for your overall health. It can help to increase your strength and energy levels, and reduce the risk of other types of health problems.  

Try to: 

  • Drink plenty of fluids  
  • Eat a balanced diet 
  • Eat little and often if you don't have an appetite 
  • Eat when your appetite is at its best 
  • Pre-prepare and freeze food when you have energy. 


Taking time to relax is also important. It gives your mind time to switch off and be free from stress or worry. You could try a relaxation technique, or something to distract yourself, like doing a puzzle or reading a book. 

To help reduce stress, set yourself goals that you know you can manage. If you try to do too much, you may feel frustrated that you’re unable to do everything you’d planned to do.

Even if you follow all of the tips above to improve your energy, it may still not be at the level it was before your treatment. It’s common for people with low energy to follow a pattern which is called the ‘boom and bust’ cycle. Below we explain how it works and look at ways to overcome it so that you can make the most of the energy levels you have.

  • On a day when you have lots of energy you may overdo things. 
  • The following day you are more fatigued, which means you need to rest more or do less. 
  • When your energy improves, you start to do more again.

What happens if I follow the boom and bust cycle?

  • Your fatigue is likely to be worse than if you paced your activity. 
  • You spend more time resting compared to the time you spend doing activities. This may make it harder for you to be active. 
  • You may find it difficult to make or commit to plans in case you need to cancel them if you’re feeling fatigued. 
  • This may make you feel frustrated and think you have failed. 

Reasons why some people may be following the boom and bust cycle

  • There may be work that ‘has to be done’ or things you want to do. 
  • You may feel better when you finish a task rather than leave it to finish another time. 
  • You may feel guilty about overloading others. 
  • You may try to ignore or beat the fatigue. 

Overcoming the boom and bust cycle

You can overcome this cycle by doing the following: 

  • Prioritising 
  • Planning 
  • Pacing 
  • Permission. 

You can remember these as ‘4 Ps’. 

1. Prioritise

You may find it helpful to prioritise your tasks and activities. This way you can use your energy for things that you need to do, instead of wasting it on tasks that don’t need doing. 

You can learn to prioritise tasks and activities by following the suggestions below: 

  • Write down tasks and activities for the week, including things you must do and things you enjoy doing. 
  • Work out which of these things need to be prioritised. 
  • Then, work out if there are things someone else can do, if that’s possible. 
  • Think about the amount of energy each task will use (high, medium or low). Use a table similar to the one below to help you prioritise your tasks and activities. 

Priority (P)

Non-priority (NP)

Someone else can do (SE)

Amount of energy used:


Make breakfast P Medium
Call sister NP High
Walk dog SE High

2. Plan your day/week 

  • First, write down in a diary the tasks and activities that you have identified as priorities. It may help to colour code the activities, depending on whether they use low, medium or high energy. 
  • Schedule in periods or rest or low-energy activities before and after the ones that use high levels of energy. 
  • Avoid scheduling high-energy activities close together. 
  • Schedule in activities that you enjoy doing or that restore your energy.

3. Pace yourself 

If you work at a slower pace, your energy will last longer. Before you start a task or activity think about the following: 

  • Stop before you get fatigued. It may help to complete a fatigue diary for one week to see if there is a pattern to your fatigue. 
  • Break tasks into smaller, more manageable chunks and rest in between these. 
  • Use equipment to help with tasks (like a vegetable chopper or tumble dryer). 
  • Sit rather than stand for tasks where possible. 

4. Permission

  • Give yourself permission to stop and rest when you feel you need it. 
  • You don’t have to do it all yourself – ask for help from friends and family if possible. 
  • Don’t be hard on yourself if you are unable to do certain tasks.

  • Ask your healthcare team to refer you to an occupational therapist. 
  • Visit to download the Macmillan booklet or audiobook ‘Coping with fatigue’. 
  • Visit our health and wellbeing resources web page: 

University College London Hospitals NHS Foundation Trust cannot accept responsibility for information provided by external organisations.

Macmillan Support and Information Service Helpline: 020 3447 3816 

General enquiries: 020 3447 8663 


X (formerly known as Twitter): @supportandinfo 


Page last updated: 10 July 2024

Review due: 01 July 2026