Headache when standing up

Standing moves blood downward and the body must adjust circulation. If you have had too little fluid, been in the heat, been unwell, or stayed in bed, that adjustment may bring headache, light-headedness, blurred vision, weakness, or a feeling of near-fainting. Dehydration and Heat Exhaustion can contribute. A Common Cold or COVID-19 may reduce fluid intake and add fatigue. Medicines, bleeding, anaemia, or a blood-pressure problem can also cause postural symptoms and require clinical assessment.

Pay attention to whether the pain starts within moments of standing, settles after sitting or lying down, and occurs with palpitations, breathlessness, fainting, fever, vomiting, or unusually heavy bleeding.

Rise in stages: sit on the edge of the bed, move your ankles, then stand while holding a stable surface. Sit or lie down immediately if you feel faint, and do not drive or climb while symptoms are active. Drink fluids regularly if you have no medical restriction, and cool down after heat exposure. Keep a note of posture, timing, meals, fluids, medicines, and symptoms. Arrange a medical review if episodes repeat, last longer, or interfere with normal activity.

Call emergency services for fainting with injury, chest pain, severe breathlessness, a sudden severe headache, confusion, seizure, new weakness or numbness, trouble speaking, or loss of vision. Seek prompt care for repeated near-fainting, inability to keep fluids down, severe heat illness, black stools, or heavy bleeding.

Could dehydration, heat, a medicine, or a blood-pressure change explain this? Should my pulse, blood pressure, blood count, or hydration be checked? How should I respond if I feel faint again?