If you often feel dizzy or faint after standing up, consider having your blood pressure checked. Low blood pressure (hypotension) is often due to dehydration, but can also be the result of sodium loss, abnormal heart rhythms, neurological disorders or overly aggressive drug treatment for high blood pressure. Low blood pressure can result in dizziness, lightheadedness or even fainting.
To help address dizziness, you may want to stand or sit up more slowly, and have a person or piece of furniture nearby for support when you do. Any qualified healthcare provider, or even the staff at a local fire station, can perform a simple blood pressure check in minutes.