There are 4 main symptoms of myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS).

Extreme tiredness (fatigue)

The extreme tiredness (fatigue) associated with ME/CFS does not go away with rest or sleep. This can make it difficult to carry out everyday tasks and activities.

Most people with ME/CFS describe their fatigue as overwhelming and a different type of tiredness from what they've experienced before.

Problems sleeping

Many people with ME/CFS also have serious problems with their sleep that do not get better.

You may find that:

• you do not feel refreshed after sleeping – like you have not had a proper good night's rest
• you keep waking up during sleep
• you feel stiff, tired or have flu-like symptoms when waking up
• you feel very tired and sleepy during the day

Problems with thinking, memory and concentration

If you have ME/CFS, it's also common to:

• have problems remembering certain words, names or numbers
• have difficulty concentrating or difficulty focusing on more than one thing at a time
• have problems remembering things that happened recently
• be slow to speak or react to things

These problems are sometimes described "brain fog".

Post-exertional malaise (PEM)

Symptoms of ME/CFS can get worse after activity (called post-exertional malaise, or PEM).

PEM can be triggered by physical or mental activity, such as socialising or studying

PEM can happen hours or days after the triggering activity, and it can take weeks to recover.

Other symptoms

Other symptoms of ME/CFS can include:

• muscle or joint pain
• headaches
• a sore throat or sore glands that are not swollen
• flu-like symptoms
• feeling dizzy or sick
• fast or irregular heartbeats (heart palpitations)
• muscle twitches or spasms
• intolerance to alcohol or certain foods or chemicals
• being very sensitive to light, sound, touch, taste and smell
• having hot flushes or cold chills if the temperature changes
• feeling dizzy, sick or fainting when standing up from a sitting or lying position

Severity of symptoms

Most cases of ME/CFS are mild or moderate, but 1 in 4 people have severe symptoms.

If your symptoms are severe, a specialist should be involved in your treatment.

ME/CFS symptoms can be considered:

• mild – you’re able to care for yourself but may have problems moving around; you may be able to go to work or school, but will not have energy to do much else
• moderate – you may have difficulty moving around easily and problems carrying out daily activities; you may not be able to work or continue with your education and may need to rest often; you may also have problems sleeping at night
• severe – you may not be able to do any activity, or only be able to do very basic daily tasks, such as brushing your teeth; you may be housebound or even bedbound and need a wheelchair to get around; you may also have difficulty concentrating, be sensitive to noise and light, and take a long time to recover after activities involving extra effort, such as leaving the house or talking for long periods
• very severe – you may have to spend all your time in bed resting and be fully dependent on carers; you may need help eating, washing and going to the toilet; you may be extremely sensitive to light and noise; you may be unable to swallow and need to be fed using a tube

There may be times when your symptoms get worse. These periods are known as relapses.

ME/CFS and work

If you have to take time off work, you may feel able to return to work in the future. But a sudden return to full time work may not be possible.

By law, your employer must make reasonable adjustments to help you do your job.

The ME Association has A Guide to Employment Issues that you may find useful.

What else could it be?

The symptoms of ME/CFS are similar to those of other conditions.

If you think you may have ME/CFS it's important to see a GP to make sure you get a correct diagnosis. A GP should also be able to refer you to a ME/CFS specialist if they think it would help you.