Does postural hypotension cause fainting?

Postural hypotension, also called orthostatic hypotension, happens when blood pressure falls after moving from sitting or lying to standing. The body normally tightens blood vessels and adjusts the heartbeat to keep blood reaching the brain. If that response is delayed or insufficient, you may feel light-headed, weak, unsteady, or see spots. Fainting occurs when the temporary reduction in brain blood flow is enough to make you lose consciousness briefly. Dehydration, illness, heat, prolonged bed rest, and some medicines can contribute.

At the first warning, sit or lie down straight away and raise your legs if practical. Stay there until you feel fully alert, then change position slowly: roll to your side, sit at the edge of the bed, and stand with support. Drink fluids if you have not been told to restrict them. Keep a record of when episodes happen, your position, food and fluid intake, and medicines. A clinician can check blood pressure while you change position and review possible causes.

Arrange medical assessment after any unexplained faint, especially if episodes recur or cause an injury. Seek urgent help if fainting happens during exercise, while lying down, or with chest pain, trouble breathing, a racing or irregular heartbeat, severe headache, confusion, weakness on one side, or ongoing bleeding. Do not drive until a clinician has advised that it is safe.

Could my medicines, dehydration, anaemia, heart rhythm, or another condition be lowering my blood pressure? Should I check my blood pressure at home, and which readings or symptoms should prompt contact? What steps can I take before standing or during hot weather?