ME/CFS (Chronic Fatigue Syndrome): Symptoms, Diagnosis and Pacing

ME/CFS isn’t ordinary tiredness. It’s a long-term illness in which physical or mental effort can trigger a crash of symptoms, often a day or two later. For years, many people weren’t believed. Guidance has now changed, and understanding the illness is the first step to managing it.

Imagine feeling well enough on Saturday to go food shopping and meet a friend for coffee. On Monday you can barely get out of bed: aching muscles, a pounding head, a brain that won’t work. It lasts for days. Your family says “but you were fine on Saturday.” That delayed crash is the hallmark of ME/CFS.

Key symptoms

• Debilitating fatigue not relieved by rest
• Post-exertional malaise: symptoms worsening after activity, often delayed
• Unrefreshing sleep
• Problems with thinking, memory and concentration (“brain fog”)
• Often dizziness on standing, pain, and sensitivity to light and noise

Diagnosis

There’s no single test. Doctors diagnose ME/CFS based on symptoms lasting several months and by ruling out other causes of fatigue, such as anaemia, thyroid disease, depression and sleep disorders.

Managing ME/CFS

• Energy management (pacing): staying within your energy limits to avoid crashes
• Treating symptoms such as pain, sleep problems and dizziness
• Support with work, school and daily life

But isn’t exercise the answer?

Not in the way it was once thought. Updated guidance, including from NICE in the UK and the US CDC, no longer recommends graded exercise therapy that pushes people to steadily increase activity regardless of symptoms, because it can make some people worse. Any activity plan should be personalised and led by how you respond.

Sources: NICE guideline on ME/CFS (2021), US Centers for Disease Control and Prevention (ME/CFS), NHS (ME/CFS). This guide is for general information and does not replace advice from your own nurse or doctor.