What is fatigue?

managing 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 rheumatoid arthritis (RA) you may experience a tiredness that’s quite different in quality and intensity and which doesn’t always improve after rest.

Fatigue is a common symptom of rheumatoid arthritis.

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 people 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 RA (just like pain and joint stiffness), and you can learn to manage it successfully.

Feelings 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 RA:

Active disease

RA cuases inflammation in your joints and other tissues, and this can cause fatigue. 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.

Drug treatment

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


Pain caused by your RA can wear you down, especially if it’s constant, and contribute to fatigue.

Muscle weakness

Inactivity due to pain or joint problems 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

Pain and difficulties with joints and muscles can make it more difficult for you to do tasks they would previously have found easy. 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 and should be avoided. Instead pace yourself.

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.

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.