Many people with normal (or even elevated blood pressure) occasionally experience a temporary drop in blood pressure upon rising quickly. This form of low blood pressure, called orthostatic hypotension, may cause you to feel momentarily faint, or light-headed, but quickly passes. If you experience orthostatic hypotension frequently you may want to take precautions against falling, such as getting up more slowly and holding on to a support.
Low blood pressure can be caused by certain medications or treatable diseases. If you have symptoms of low blood pressure, such as dizziness, weakness, and fatigue, you should be sure to talk with your doctor about other possible causes.