Fatigue

Fatigue is a feeling of subjective feeling of tiredness, often called by other names including exhaustion. Persistent physical fatigue is a core symptom of chronic fatigue syndrome and a common symptom in many other chronic health conditions.

Types of fatigue
A number of different types of fatigue have been described in people with ME/CFS: 
 * 1) Post-exertional fatigue
 * 2) Wired fatigue (wired but tired)
 * 3) Brain fog
 * 4) Lack of energy for daily living activities
 * 5) Flu-like fatigue

Symptom recognition
Persistent fatigue which is not relieved by rest, not life-long, persist over the long term, and does not result from another health condition is a compulsory symptom of chronic fatigue syndrome in the Fukuda criteria.

Multiple types of fatigue are common but optional symptoms of the International Consensus Criteria and Canadian Consensus Criteria for Myalgic Encephalomyelitis.

Fatigue is one of the most common Long COVID symptoms.

Notable studies

 * 2009, Examining Types of Fatigue Among Individuals with ME/CFS (Full Text)
 * 2010, Classification of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome by Types of Fatigue (Full Text)
 * 2014, Chronic fatigue syndrome: A review (Full Text)


 * 2016, The aetiopathogenesis of fatigue: unpredictable, complex and persistent (Full Text)
 * 2018, Association of sleep disorders, chronic pain, and fatigue with survival in patients with chronic kidney disease: A meta-analysis of clinical trials (Full Text)

Learn more

 * 19 Important Causes of Fatigue – Tiredness and Chronic Fatigue Explained


 * 2010, Classification of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome by Types of Fatigue (Full Text)