Re: Blood pressure and feinting

I thought feeling feint was caused by lack of blood and consequently oxygen in the brain.

The heart is a pump, and when you stand up the blood pressure in the brain falls. The heart has to pump harder to get the blood and oxygen back into the brain, and this takes a few seconds, during which time you feel feint. That's why the solution is to sit or lie down again, or just stay still and wait until the heart pumps the blood. Of course if you do feint, your head will quickly be back at ground level, thus evening out blood pressure across the entire body and rectifying the problem. Fortunately the heart keeps pumping even if we do bang our heads on the way down.