[miriam_catira]

Yep, fainted so, so many times... Always seems to happen after getting hurt on or near a nerve for me - or after a blood draw. Was scary the first time, embarrassing and annoying every time since then. :) Had a nurse explain that the best way to prevent it is flexing / tightening the legs, to force the blood up out of them. Seems to work, at least for me.

[BrianB]

That works for me too. A cardiologist told me it is because it gives your body a reason to keep the blood pressure higher. He also advised drinking lots of water every day.

[teeray]

Fighter pilots are trained to contract their solar plexus by making a “hut” sound to do something similar when they’re passing out. I was going to try this the last time I was fainting after a blood draw, but was interrupted by the phlebotomist imploring me to breathe slow and deep—I think this just sunk me further into it.

[lukas099]

Valsalva maneuver against a closed glottis. As someone prone to blacking out when standing up or after a set of heavy squats, figuring this out has been very useful to me.

[Fire-Dragon-DoL]

Is it while standing or laying down? I don't faint if I lay down.

Also if I pass a crisis without fainting, I get immunity for a good while