In a patient with orthostatic hypotension, how does the body's compensatory response generally manifest?

• A. Increased cerebral blood flow
• B. Decreased heart rate
• C. Increased sympathetic outflow
• D. Decreased arterial pressure

Answer: (C)

In someone experiencing orthostatic hypotension, the body typically responds by increasing sympathetic outflow. When a person stands up, gravity causes blood to pool in the lower extremities, leading to a drop in blood pressure, which can cause symptoms like dizziness or fainting. The baroreceptors, located in the carotid sinus and aortic arch, detect this drop in arterial pressure and send signals to the central nervous system.

In response, there is an activation of the sympathetic nervous system. This leads to several physiological changes: increased heart rate (to help maintain cardiac output), vasoconstriction (to increase systemic vascular resistance), and enhanced contractility of the heart. This compensatory mechanism aims to restore blood pressure to a normal range and improve cerebral perfusion by directing blood flow back to vital organs. Therefore, increased sympathetic outflow is a crucial part of the body's effort to counteract the effects of orthostatic hypotension.