Hypotension is defined as blood pressure that is below normal for an individual. Hypotension is the opposite of hypertension, which is abnormally high blood pressure.
When blood pressure drops below a certain level, oxygen and other nutrients are not efficiently delivered to the brain. This can lead to dizziness and fainting, or it can be an indication of other serious medical conditions. Severely low blood pressure can lead to a life-threatening condition called shock.