What is this article about?
Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), is a complex, chronic neurological condition affecting the brain, muscles, digestive system, immune system, cardiac system and other areas of the body. ME/CFS is characterised by post-exertional malaise (PEM), which describes the worsening of symptoms after physical or mental activity. Some people might experience PEM after going on a walk, while those with a more severe illness might trigger it by simply brushing their teeth or reading a sentence. Once triggered, PEM may persist for days, weeks or months. The cause of ME/CFS is not yet understood and there is no cure.