Lightheadedness makes a person feel that he or she is about to
faint or pass out. It is caused by a momentary drop in blood pressure and blood
flow to the head.
Nausea or vomiting sometimes accompanies lightheadedness. Symptoms
usually improve or go away after lying down.
It is common to feel lightheaded occasionally. Lightheadedness
often occurs when a person gets up too quickly from a seated or lying position
Unlike vertigo, lightheadedness does not produce a sensation of
movement. Vertigo causes a spinning or whirling sensation that may lead to
nausea or vomiting, loss of balance, trouble walking or standing, and
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & David Messenger, MD