| Post-exertional malaise (PEM) is a worsening of symptoms, disproportionate to the physical, cognitive, emotional, or orthostatic exertion that precipitated it, typically with delayed onset and a prolonged recovery period that may extend from hours to weeks. Commonly reported symptoms include increased fatigue, cognitive dysfunction, pain, and flu-like or orthostatic symptoms. Distinct from a simple increase in tiredness following activity. |
