Alcohol can induce fainting spells

The reflex-feedback system in the human body is a person’s answer to gravity. When people stand up, gravity tries to pull the blood in their systems downward. To keep circulation in equilibrium, the veins and arteries constrict momentarily, thereby maintaining blood pressure.

Alcohol dilates blood vessels and impairs this reflex, which may explain why some people faint upon standing after downing only a few drinks, Virend K.