What Causes It?
Viral infections (such as Epstein-Barr virus or human herpesvirus 6)
Immune system dysfunction
Hormonal imbalances
Physical or emotional trauma
Genetic factors
Stress and environmental factors
Signs & Symptoms
Extreme fatigue that doesn't improve with rest
Post-exertional malaise (worsening of symptoms after physical or mental activity)
Unrefreshing sleep
Cognitive difficulties ("brain fog")
Orthostatic intolerance (dizziness when standing)
Muscle and joint pain
Headaches
Sore throat
Tender lymph nodes
Digestive issues