What should you know about overwhelming fatigue?

Fatigue may feel like heavy limbs, poor concentration, low energy or a need to sleep despite rest. It can occur with an infection such as COVID-19, dehydration, anaemia, coeliac disease, burnout, alcohol use disorder, chronic kidney disease or chronic fatigue syndrome. These conditions have different patterns and need different evaluations.

A clinician will ask when it began, whether it fluctuates, how sleep and mood are affected, and about bleeding, pain, fever, weight change, medicines and substance use. Examination and selected tests may help clarify the cause.

For a few days, record sleep, activity, meals, fluids, symptoms and any recent infection. Keep activity gentle and balanced with rest; avoid pushing through a marked crash. Drink regularly and eat nourishing meals if you can, and review medicines with a clinician rather than stopping them yourself.

Arrange primary-care advice when fatigue limits work, study, self-care or usual movement, or does not settle. Bring your symptom record and mention snoring, mood changes or menstrual and gastrointestinal symptoms.

Seek urgent help for chest pain, severe breathlessness, fainting, new confusion, one-sided weakness, black or bloody stools, or inability to keep fluids down. Prompt review is also appropriate with persistent fever, marked paleness, unexplained weight loss or severe low mood with thoughts of self-harm.

What causes fit my pattern of fatigue? Do I need blood or urine tests? Could sleep, mood, diet, bleeding, infection or a medicine be involved? What activity level is safe while this is investigated?