What is fatigue?

What is fatigue?

Fatigue is a feeling of extreme physical or mental tiredness, or both. Most of us feel tired after a long day, but if you have a long-term medical condition such as cancer you may experience a tiredness that’s quite different in quality and intensity and which doesn’t always improve after rest.

What are the features of fatigue?

Common features of fatigue include:

  • your body and limbs feeling heavy and difficult to move
  • flu-like feelings of exhaustion
  • the feeling that your energy has drained away.

Many people also report mental fatigue, when they can’t think straight and lose their concentration or motivation. Some patients refer to this as ‘brain fog’. Some people report an emotional fatigue which makes them irritable, down or tearful. This fatigue isn’t the same as chronic fatigue syndrome, it’s a symptom related to cancer, and you can learn to manage it successfully.

Attacks of fatigue may occur at any time of the day. You may experience it when you wake up, so you don’t feel refreshed from sleep, or it may come on when you’re physically busy or concentrating a lot. For many people, fatigue seems to have no clear cause and happens without warning. It may last anywhere from an hour to the whole day and could continue over several days or weeks at a time, although this is less common.

Fatigue can have a major impact on your life. It can force you to stop what you’re doing and rest, or make you change your plans. This can have a big effect on your ability to run your life or do the things that we all take for granted.

When fatigue is severe, it can lead to feelings of complete exhaustion, or ‘wipe-out’, when you have to sit or lie down to try to recover. This may be made worse by a lack of understanding from others about how much it affects you – show this information to friends and family to help you explain your experiences.

How is fatigue measured?

There’s no direct way of measuring fatigue, but your rheumatology team or GP can assess how it’s affecting your life. You may be given a questionnaire to report the extent and effects of fatigue, which can guide your doctors to self-help strategies that you might be able to use. The questionnaire might ask you to assess:

  • how severe the fatigue is
  • the level of distress it causes you
  • your physical and mental tiredness
  • the impact on your daily life
  • how much you feel able to cope 

What causes fatigue?

The following factors may contribute to fatigue in cancer:

Cancer Treatment

Cancer treatment such as chemotherapy, radiotherapy and surgery can be a cause of the fatigue.

Active disease

Chemicals called cytokines, which are found in inflamed tissues, are similar to chemicals released in viral illnesses such as colds and flu, and they can cause extreme fatigue.

Anaemia sometimes occurs with inflammation, and this can also cause fatigue.

Long-term conditions

Diabetes and thyroid problems can cause fatigue.

Drug treatment

Some drugs used to treat cancer-related pain may cause drowsiness, loss of concentration and light-headedness.


Pain is a major symptom of most types of cancer and it can wear you down, especially if it’s constant.

Muscle weakness

Inactivity can cause your muscles to become weak, which may contribute to fatigue because it’ll take more effort to make your joints work. When you’re less physically active you can become unfit, and this can also cause fatigue.

Overdoing it

Often people will keep going even after they know they should stop (for example when doing a physically challenging activity such as gardening), which can cause exhaustion for hours or days afterwards. This is called ‘boom and bust’ behaviour.

Stress or anxiety

Your body’s natural reaction to deal with stress is to release a hormone called adrenaline, which prepares your body to deal with a crisis (your muscles, heart and lungs work harder and your mind becomes very alert).

This adrenaline release usually only lasts until the crisis passes, but if the stress continues (for example because of constant pain or anxiety about the future) and your body carries on releasing adrenaline, it can cause physical and mental exhaustion.

Sleep disturbance

If your sleep is disturbed due to pain, anxiety or stress, it can cause fatigue. Too much sleep can also make you fatigued, particularly going back to sleep in the day.

Click the link to view our factsheet on sleep – https://www.opa.org.uk/edit/files/sleep.pdf

Low mood or depression

Sometimes people with a long-term condition feel down and uncertain about the future. This can lead to low mood or perhaps depression, which reduce energy or cause the feeling of fatigue.

Poor diet or hunger

A poor diet or missing meals may result in a lack of energy.

It’s likely that no single factor causes fatigue but that several combine and interact with each other. The combination may be different for everybody and vary each time.

For example, your fatigue might be driven by inflammation, which also causes pain and disturbed sleep, but at another time you might be fatigued largely because of stress from a family crisis, which means you overdo things as you deal with it and end up missing meals.

How can I help myself?

There are many things you can do to reduce the impact of fatigue. Start by working out the possible causes then talk to your healthcare team so they can look at different ways to help you manage it.

If you think your drug treatment may be causing your fatigue, talk with your doctor about reviewing your treatment. They can also look for signs of other conditions that may be causing fatigue, and check your inflammation or anaemia levels.

If you have signs of active inflammation, your doctor may alter your medication to improve your symptoms, which will help to ease fatigue. However, it’s unusual to make major changes to drug treatments to control fatigue unless there’s significant evidence of inflammation as well.

No specific drugs can treat cancer-related fatigue, but there are many ways that you can reduce the impact of fatigue on your life without medication. Changing behaviours like this does work, but most of us need support to do it, so discuss this information with your GP or rheumatology team, who should be able to help you work through it (particularly your occupational therapist, rheumatology nurse specialist or physiotherapist).

Try combining some of the following tips on self-management.

The four Ps

When people feel fatigued, they often spend their energy on work and chores and give up things that they enjoy. Use the four ‘P’s’ to help you to conserve your energy, work out what’s important to you and give you time for things you want to do:

Problem solving

Often it’s not what you do, it’s the way that you do it that makes a difference. Look at your daily routine. Start to notice if you spend all morning doing the same type of repetitive tasks or if your working position causes you pain or discomfort. Perhaps your body complains when you do certain tasks or you get very tired by the afternoon.

If a task causes you a problem, ask yourself how you can do it differently.


Make a plan of the things you want to achieve during the day or over the week. Plan how and when you’re going to do certain tasks, and spread them out wherever possible over a number of days.

Make sure that demanding jobs are spaced out during each day or week.


If you list the tasks you need to do, you can put them in order of importance and decide what tasks you can remove, delay or hand over. Ask yourself the following:

  • Does this need to be done today?
  • Does it need to be done at all?
  • Do I have to do it, or can someone else?
  • Can I get someone to help me with parts of the task? 


Break tasks down into achievable parts and spread them throughout the day or week, and take short, regular rest breaks. Change your position and activity regularly.

Don’t use exhaustion as a guide for when to stop – change your task or rest before you start to feel tired.

You may have found that fatigue has stopped you doing things you really want to, so it’s worth spending some time thinking what you could achieve that would make you feel good (for example socialising with friends or getting back into a hobby).

Setting yourself small, weekly goals can help you build up to what you really want to do as you start managing your fatigue. You’re much more likely to meet small, specific goals than vague ones or ones that aim too high. Your occupational therapist or rheumatology nurse specialist may be able to help you set and review goals.