All questions about ME/CFS and long COVID

What is post-exertional malaise?

Symptoms getting worse after physical or mental activity, often hours or days later, and taking days or weeks to recover. It's the defining symptom of ME/CFS.

Triggers include socialising and studying, not just physical effort. The worsening is out of proportion to what was done. It's why pacing matters so much.

Sources

• NHS: ME/CFS, symptoms
• ME Association: What are ME/CFS and long COVID? (summarises the NICE 2021 guideline)
• CDC: Manage ME/CFS

Reviewed 2026-11-09 · next review 2027-11-09