What should you know about fainting when sick?

Vomiting, diarrhoea, fever, sweating, or reduced drinking can lower body fluid and blood pressure. Poor appetite may also leave the body short of energy. Standing after lying down can then bring on dizziness, blurred vision, or collapse. Dehydration and hypoglycaemia are possible contributors; anaemia and an irregular heart rhythm are other causes a clinician may consider.

Fainting is different from feeling weak throughout an illness. Record whether awareness was lost, how long recovery took, and whether there was fever, bleeding, palpitations, pain, or breathlessness. This helps separate a simple faint from a condition needing prompt treatment.

At the first hint of faintness, lie down and raise your legs, or sit with your head lowered. Ask someone to stay nearby. Once fully alert, take small frequent sips of suitable fluid and follow medical advice about oral rehydration. Eat a light meal when able unless fasting has been prescribed. Rest, avoid heat, and rise in stages rather than walking suddenly.

Seek emergency help for confusion, difficulty breathing, chest pain, severe abdominal pain, blood loss, a severe headache, new weakness, seizure activity, serious injury, or delayed recovery. Get prompt medical advice if you cannot keep fluids down, are passing very little urine, faint repeatedly, faint while exercising, or have known heart disease. Children, older adults, and pregnant people may need earlier review.

Ask whether your illness requires a fluid plan, blood tests, medicine adjustment, or heart assessment. Explain your recent intake, losses from vomiting or diarrhoea, temperature, medicines, and any fainting warning symptoms.