Postural hypotension is best described as changes in arterial pressure when moving from a supine or seated position to an upright position.

• A. Increases in blood pressure only
• B. No change in blood pressure
• C. Changes in arterial pressure when moving upright
• D. Decreases in heart rate only

Answer: (C)

Postural hypotension happens because standing up causes a real change in arterial pressure due to gravity. When you rise from lying or sitting, blood tends to pool in the legs and abdomen, which lowers the amount returning to the heart. That can reduce the amount the heart pumps (so arterial pressure drops) unless the body's reflexes quickly compensate by speeding up the heart and tightening blood vessels. The defining idea is that arterial pressure changes when you go upright, not that it always goes up or down in one direction or that it changes only the heart rate. In healthy people, the body adjusts quickly; when it doesn’t compensate enough, you get orthostatic symptoms.