What does "orthostatic hypotension" refer to?

Orthostatic hypotension refers specifically to a drop in blood pressure that occurs when a person stands up after sitting or lying down. This condition can lead to symptoms such as dizziness, lightheadedness, or even fainting due to insufficient blood flow to the brain as a result of the sudden change in posture. When a person stands, gravity causes blood to pool in the lower extremities, and if the body's mechanisms do not prompt an adequate compensatory increase in heart rate and constriction of blood vessels, the resultant drop in blood pressure can lead to the symptoms associated with orthostatic hypotension.

The other options do not accurately describe this condition; for example, a rise in blood pressure upon standing is typically the opposite of what occurs in orthostatic hypotension, while an increase in heart rate can be a compensatory mechanism rather than a defining factor of the condition. Similarly, consistent low blood pressure regardless of position does not capture the essence of orthostatic hypotension, which specifically relates to the change of position from sitting or lying down to standing.