Extreme fatigue: what to know

Fatigue can follow disrupted sleep, emotional strain, infection, dehydration or not eating enough. Anaemia may reduce oxygen delivery and bring breathlessness, paleness or a racing heartbeat. Thyroid, kidney or other long-term conditions can also lower energy. Coeliac disease may affect nutrition, while burnout and alcohol use disorder can disturb sleep, mood and physical stamina. Some people develop prolonged exhaustion after an illness, including COVID-19. Chronic fatigue syndrome is a separate diagnosis that requires a careful clinical assessment; fatigue alone cannot establish its cause.

Keep a simple record of sleep, meals, fluids, activity, medicines and accompanying symptoms. Set a steady sleep routine, eat regular balanced meals and drink enough to avoid thirst or dark urine. Break demanding tasks into smaller periods with rests, and avoid suddenly pushing through exhaustion. Do not rely on large amounts of caffeine or alcohol to manage energy. A clinician may review your history, examine you and arrange tests guided by your symptoms.

Book an appointment if fatigue is persistent, worsening, interfering with work or self-care, or accompanied by weight change, fever, low mood, bleeding, breathlessness or unusual thirst. Seek urgent help for chest pain, severe breathing difficulty, fainting, new confusion, one-sided weakness or thoughts of self-harm. Immediate assessment is also sensible when you cannot keep fluids down or feel too weak to stand safely.

Ask what causes fit your pattern of symptoms, whether your medicines or sleep could contribute, and whether blood or urine tests are appropriate. Share changes in mood, diet, periods, snoring, alcohol use, recent infection and any effect on work or driving.