Myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS), is a long-lasting health condition that drains the body of energy and limits what a person can do. Even after plenty of rest, they still feel exhausted. Simple tasks that used to be easy—like going to work, school, or meeting friends—can become difficult or even impossible. In severe cases, they may be confined to their home or bed.

ME/CFS can develop suddenly, often after an illness, or come on slowly over time. What makes it particularly frustrating is its unpredictability. The moment they push beyond their energy limits—whether mentally, physically, or by standing too long—their symptoms can flare up badly. This is known as post-exertional malaise, and it’s one of the condition’s most telling signs.

What Causes It?

The exact cause of ME/CFS is still a mystery. However, researchers believe it can be triggered by certain viral infections. For example, some people developed ME/CFS after illnesses like mononucleosis or even COVID-19. In fact, many people with long COVID experience symptoms that closely match those of ME/CFS.

There’s also evidence that genes may play a role. When one family member has it, others are more likely to develop it too. The immune system might be involved as well, since people with ME/CFS often have allergies, food sensitivities, or frequent infections.

Who Is Most at Risk?

While ME/CFS can affect anyone, it’s more common in certain groups. It occurs two to four times more often in women than in men. It usually starts in teens or young adults, rarely before age 10, and it’s not something that typically shows up in older age.

Interestingly, many young people with ME/CFS have unusually flexible joints, sometimes called “double-jointed.” This condition, known as joint hypermobility, appears to raise the risk, although the exact connection is still being studied.

What Are the Symptoms?

The main symptom is a deep, ongoing fatigue that doesn’t improve with rest. But ME/CFS involves much more than just tiredness. The person may feel dizzy or lightheaded, have poor concentration or memory, and still wake up feeling unrested no matter how long they sleep.

What makes ME/CFS especially challenging is how it forces the person to change their entire lifestyle. Things they once enjoyed—walking, socializing, or working—may now take a toll on their health. But recognizing the symptoms and getting a proper diagnosis can be the first step toward managing the condition and improving quality of life.

While there’s no cure yet, raising awareness about ME/CFS is vital. It’s a real condition that deserves understanding, compassion, and continued medical research.