Post-Exertional Malaise in Chronic Fatigue Syndrome

By Jennifer Spotila, J.D. for The CFIDS Association of America, 2010

Part One – Unraveling Post-exertional Malaise

Muscle wilting meltdown, air gulping short of oxygen feeling, brain blood vessels flayed on a laundry line in the wind, metal rods in the back of head . . . someone crushing your ribcage, limbs giving out, mesh bag constricting head, ‘pingers’: those first small headaches that warn of bigger headaches, ‘back of head clamp’ . . . headache, increased gravity feeling, being pushed backward into bed, temple-to-temple headache, weak arms as if bound down by stretchy ropes, eyes and brain blanking with a kind of pulse through the head . . . Harm and damage often come from these collapses, though on the outside they may look like ‘malaise’.
– Patient, speaking anonymously

A survey of more than 1,000 patients conducted by The CFIDS Association in 2009 found that post-exertional malaise (PEM) is one of the most common and most severe symptoms reported by patients. This article, the first in a series, examines the definition of PEM and how patients experience it.

How Is Post-exertional Malaise Defined?

Standard medical dictionaries define malaise as “a feeling of general discomfort or uneasiness, an out-of-sorts feeling.” This bland description bears little resemblance to the severity of PEM in CFS. It is not clear who first coined the term or applied it to CFS. Early definitions of the illness do not use the phrase, but they do describe something like it.

The 1988 Holmes criteria for CFS included the symptom of “prolonged (24 hours or greater) generalized fatigue after levels of exercise that would have been easily tolerated in the patient’s premorbid state.” The Oxford criteria  from 1991 said only that fatigue and myalgia (muscle pain) “should be disproportionate to exertion.” Neither Holmes nor Oxford required PEM for diagnosis of CFS. The 1994 Fukuda criteria6 was the first to explicitly include the symptom of “post-exertional malaise lasting more than 24 hours,” but still did not require it in order to make a diagnosis of CFS.

Read the full report here.