Myalgic Encephalomyelitis (ME), sometimes referred to and diagnosed as Chronic Fatigue Syndrome (CFS), is a chronic, fluctuating disease, causing symptoms such as post-exertional malaise (PEM), sleep problems, problems with thinking and memory (brain fog), pain and crushing fatigue.
The hallmark symptom of ME is post-exertional (PEM) malaise. This means that simple physical or mental activities, or combinations of activities, can leave people with ME feeling utterly debilitated. They can also experience an increase in other symptoms. The impact of this may be felt straightaway but it can typically take a day or two to kick in and is not significantly improved by resting.
While there are key symptoms that must be present for an ME diagnosis, not everyone with ME experiences the same set of symptoms and the illness can vary enormously, including how long symptoms last.
One in four people with ME are so severely affected that they are house or bedbound.
Our resources below give further key information to answer the question 'what is ME?', with frequent reference to the 2021 NICE guideline to diagnosing and managing ME/CFS.
Other useful resources include our Learn about ME podcast on the NICE guideline, Introduction to ME/CFS (15 min), part of the Dialogues for a neglected illness film project and Post Exertional Malaise (PEM) (3 min) a film by ME patient, Broken Battery.
The causes of ME are still being investigated. Emerging evidence indicates there are likely to be a number of factors involved, including neurological and immunological elements, and there may be a number of different types or sub-groups of the illness.
There is evidence that certain infections, including but not limited to viruses, can trigger the illness.
Severe ME has a considerable impact on all aspects of someone's life.
Around one in four people with ME can become severely affected by the condition. They are often left house or bedbound and accessing appropriate care and support can be challenging.
98% of respondents with severe ME, in our 2019 Big Survey, stated they had stopped or reduced social contact, with 95% having stopped or reduced household tasks.
It is not clear why some people get ME while others recover; some fully and others to a degree.
Sadly the majority of people with ME remain ill for decades. A small proportion do recover fully, and others to a degree, however it is not clear why this happens.
This is why Action for ME believes we need services to support people living with ME now, and high-quality research to find effective treatments.
There are an estimated 1.3 million people in the UK with ME or ME-like symptoms, including post-exertional malaise: the hallmark symptoms of ME.
The figures vary greatly due to issues with misdiagnosis and recording (coding) of diagnosis.
More research and improvements in diagnosis and recording are needed to fully understand how many people have ME.
"The term long Covid is commonly used to describe signs and symptoms that continue or develop after acute Covid‑19. It includes both ongoing symptomatic Covid‑19 (from 4 to 12 weeks) and post‑Covid‑19 syndrome (12 weeks or more)."
A recent systematic review found that over half of long Covid patients met the diagnostic criteria for ME and other studies have identified common biological mechanisms and gene expression patterns.
Despite these advances, more research is needed to understand the disease mechanisms of long Covid and the similarities between ME and long Covid.
Read and download our useful resource, 'What is ME?.
Find out more about ME's hallmark symptom, post-exertional malaise.
People with ME often experience a wide range of symptoms. Find out more.
If you're looking for information relating getting an ME diagnosis, this resource is for you.
One in four people with ME are severely or very severely affected. Read about how we can help and other support that's available.
Explaining ME to others can be difficult. This resource is here to help guide conversations with others about your ME.
Read more about the similarities between ME and long Covid.
