Symptom cluster
Fatigue and post-exertional malaise
Exhaustion that rest doesn't fix, and crashes that follow activity by hours or days. This page covers: Post-exertional malaise (PEM/PESE), Chronic fatigue, Myalgia, Exercise intolerance / reduced VO2.
What causes it
The leading explanations, each with its evidence grade and audit status. Several are shared with other clusters.
Mitochondrial / metabolic dysfunction produces Post-exertional malaise (PEM/PESE).
EBV / herpesvirus reactivation produces Chronic fatigue.
Mitochondrial / metabolic dysfunction produces Exercise intolerance / reduced VO2.
Deconditioning (as cause) contested-cause Exercise intolerance / reduced VO2.
Dysautonomia / autonomic dysfunction produces Exercise intolerance / reduced VO2.
What has been tried
No treatment is approved. Each row shows how strong the evidence is, what outcome it was measured on, and any safety or conflict flag. Note that a drug can help a lab number without helping how you feel.
Pacing / energy-envelope management manages Post-exertional malaise (PEM/PESE).
Graded exercise therapy (GET) harms Post-exertional malaise (PEM/PESE).
Oxaloacetate (anhydrous enol) treats Chronic fatigue.
Low-dose naltrexone treats Chronic fatigue.
Metformin treats Chronic fatigue.
Fluvoxamine / SSRI treats Chronic fatigue.
H1/H2 antihistamines (fexofenadine, famotidine) relieves Chronic fatigue.
Pyridostigmine improves Exercise intolerance / reduced VO2.
Recumbent / supine-biased rehabilitation (PEM-bounded) manages Exercise intolerance / reduced VO2.
How it is measured
2-day cardiopulmonary exercise test (CPET) indicates Post-exertional malaise (PEM/PESE).
Invasive CPET (iCPET) diagnoses Exercise intolerance / reduced VO2.
A new 399-person trial suggests fluvoxamine reduces fatigue. The tracker has proposed strengthening that claim; until a reviewer accepts it, the page above shows the current audited state, not the proposal.