Understanding myalgic encephalomyelitis (ME/CFS)

Myalgic Encephalomyelitis (ME/CFS) is a complex neurological illness that can profoundly affect the lives of those who experience it.

Invisible to many people, ME/CFS can significantly reduce independence, make working or studying impossible, limit social activities, and in severe cases make even basic daily tasks extremely difficult.

The hallmark symptom: Post-Exertional Malaise (PEM)

The defining symptom of ME/CFS is Post-Exertional Malaise (PEM), also known as post-exertional symptom exacerbation.

PEM is a significant worsening of symptoms following physical, cognitive, or emotional activity, sometimes after even very small amounts of effort that would not affect a healthy person.

This worsening can last for days, weeks, or even longer depending on the severity of the illness.

The main symptoms of ME/CFS

• Severe, persistent exhaustion, which is not relieved by rest and is very different from normal tiredness.
• Post-Exertional Malaise (PEM): a significant worsening of symptoms after physical, mental, or emotional activity.
• Cognitive difficulties (“brain fog”): problems with concentration, short-term memory, and processing information.
• Sleep disturbances: unrefreshing sleep, difficulty falling asleep, or excessive sleepiness.
• Pain symptoms: frequent muscle pain, joint pain, and headaches.
• Autonomic nervous system dysfunction: dizziness, heart palpitations, difficulty standing, and digestive problems.
• Sensory sensitivities: increased sensitivity to light, sound, or other stimuli.

The severity of symptoms varies greatly from one person to another. Some people are able to remain independent with significant adaptations, while others may become housebound or bedbound in the most severe cases.

A recognized but still poorly understood illness

The World Health Organization (WHO) classifies Myalgic Encephalomyelitis among neurological diseases within the International Classification of Diseases: ICD-10: G93.3; ICD-11: 8E49 (post viral fatigue syndrome, including ME/CFS).

Despite this recognition and despite millions of people affected worldwide, ME/CFS remains largely unknown to the general public.

This lack of awareness often leads to misunderstandings, delayed diagnoses, and insufficient recognition of the limitations experienced by many people living with this illness.

Why discuss the term “Chronic Fatigue Syndrome”?

Words matter.

The term “Chronic Fatigue Syndrome” is still widely used, but it often creates a simplified image of the illness by suggesting that the main issue is simply fatigue.

ME/CFS is not ordinary tiredness. It is a complex illness involving multiple symptoms that can profoundly affect everyday abilities and quality of life.

These reactions illustrate the misunderstandings that many people with ME/CFS still face today.

Increasing awareness and understanding of this illness is therefore an essential step toward better recognition and a more accurate understanding of what people with ME/CFS experience every day.