Patients who lack baroreceptors have exaggerated blood pressure responses to stress. They have episodes of hypertension and hypotension that cause headaches and dizziness.
Patients with diseases of the sympathetic nervous system illustrate that everyday occurrences such as a change in posture or ambient temperature are stresses requiring a marked change in sympathetic nervous activity. Both physical and psychological stresses elicit large initial sympathetic neuronal responses that are subsequently damped by feedback inhibition from structures such as the baroreceptors. Damage to part of these feedback loops leads to exaggerated pressor responses to stress.
Psychosom Med. 1993 Jul-Aug;55(4):339-46