May 12 – International CFS Day: A Time for Awareness, Empathy, and New Perspectives

International CFS Day is held every year on May 12—an important occasion to raise awareness ofChronic Fatigue Syndrome (CFS) also known as ME/CFS (Myalgic Encephalomyelitis / Chronic Fatigue Syndrome) . Despite its significant impact on the lives of those affected, CFS remains a widely underestimated and often misunderstood condition. The day of action is therefore dedicated to education, solidarity, and scientific discourse.

What is ME/CFS?

ME/CFS is a complex, neurological multisystem disorder that affects the nervous system, the immune system, and energy metabolism. It is characterized by profound, long-lasting exhaustion, also known as fatigue.

According to estimates, approximately 17 million^{people worldwide1} are affected, including children and adolescents. For many of those affected, the condition leads to significant physical, occupational, and social limitations.

Symptoms

The most common symptoms include:

• Fatigue – persistent, pathological exhaustion and the primary symptom of CFS/ME
• Post-Exertional Malaise (PEM) – a significant deterioration in condition following minimal exertion
• Problems with concentration and memory (“brain fog”)
• Sleep problems despite feeling very tired
• Muscle aches, headaches, flu-like symptoms
• Circulatory problems, sensitivity to light and noise

Fatigue – more than just tiredness

Fatigue is a term often translated as “tiredness”—but that falls far short of the mark, as fatigue differs fundamentally from normal tiredness. In medical contexts, fatigue describes a state of deep, debilitating exhaustion that cannot be alleviated by sleep, rest, or recuperation.

In CFS, fatigue is not merely a symptom, but the defining characteristic. Unlike “normal” tiredness, it is profound and long-lasting— affecting the body, mind, and emotions. Furthermore, it is out of proportion to any prior exertion and can occur in episodes or be constant.

Those affected often describe fatigue as a feeling as though their body has “shut down,” accompanied by muscle weakness, difficulty concentrating, and a sense of inner emptiness. Even simple tasks like brushing teeth, climbing stairs, or having a brief conversation can feel overwhelming. Many also experience mental exhaustion, also known as “brain fog,” which impairs thinking, memory, and speech.

Fatigue is not limited to ME/CFS; it also occurs in other chronic conditions such as multiple sclerosis, cancer, rheumatic diseases, and long COVID. Nevertheless, it often goes unrecognized because it cannot be objectively measured—and because it is not outwardly visible.

Post-Exertional Malaise (PEM)

In addition to fatigue, post-exertional malaise (PEM) is a particularly defining feature of ME/CFS. PEM is characterized by a dramatic deterioration in one’s condition following even minimal physical or mental exertion. These “crashes” can last for days or weeks and often occur with a delay, making the condition difficult to plan for and highly stressful.

Research and New Approaches

Research on ME/CFS is still in its early stages—for a long time, the condition was underestimated or misclassified. The causes of ME/CFS are still not fully understood. It is only in recent years that the biological causes have come more into focus, partly due to the rise in cases of Long COVID with similar symptoms.

Current studies are examining, among other things, disturbances in energy metabolism, dysregulation of the immune system, and impairments of the nervous system. The goal is to identify reliable biomarkers and, in the long term, develop targeted therapies.

Despite many unanswered questions, international research activity is on the rise—and with it, the hope for medical progress and better care for those affected.

A Day of Solidarity – and a Call to Action

Despite the severity of the condition, ME/CFS often goes undiagnosed or is misdiagnosed—with far-reaching consequences for those affected. Many experience not only physical suffering but also social isolation, bureaucratic hurdles, and a lack of medical support. International CFS Day therefore sends a clear message:

• For more information on symptoms and the course of the disease
• For empathy toward those who are ill
• For research that seeks to identify biological causes
• For societal recognition of a serious illness

CFS is real, complex, and life-altering. This day of action reminds us that raising awareness can improve lives—through greater understanding, better medical care, and targeted research. Let’s not leave those affected to face this alone—neither their illness nor their struggle for recognition.

Sources and further information

1. German Society for ME/CFS
   Information platform with scientifically based content on symptoms, diagnosis, research findings, and the social situation.
   https://www.mecfs.de
2. Austrian Society for ME/CFS (ÖG ME/CFS)
   Professional association for Austria providing current statistics, medical recommendations, and public awareness campaigns.
   https://www.oegmecfs.at
3. National Academy of Medicine (USA)
   Groundbreaking report: Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness (2015)
   https://nap.nationalacademies.org/catalog/19012/
4. Centers for Disease Control and Prevention (CDC, USA)
   Medical definitions, research approaches, and patient information on ME/CFS.
   https://www.cdc.gov/me-cfs/
5. World Health Organization (WHO)
   ME/CFS has been classified as a neurological disorder under ICD-10 G93.3 since 1969.
   https://icd.who.int/browse10/2019/en#/G93.3
6. Charité Fatigue Center, Berlin
   University research institute specializing in fatigue and ME/CFS.
   https://cfc.charite.de
7. Euromene (European ME/CFS Research Network)
   European research network for epidemiological surveys and the coordination of studies on ME/CFS.
   https://www.euromene.eu