Traditionally, it is thought that acute control of blood pressure is accomplished by baroreflexes and the more long-term setting by renal mechanisms and renin-angiotensin. Evidence, however, indicate that baroreflexes also participate in more long-term blood pressure control, because in humans, a high salt intake can chronically suppress heart rate and increase stroke volume. Furthermore, pacing of the afferent nerves from the carotid sinus to the central nervous system can decrease blood pressure in hypertensive patients resistant to medical treatment. There is also evidence that the renin-angiotensin system participates in acute control of blood pressure, because during orthostatic interventions, individuals with attenuated responsiveness of renin-angiotensin are more prone to fainting. Furthermore, suppression of renin-angiotensin is a necessity for preventing blood pressure from increasing during acute central blood volume expansion by water immersion in humans. That baroreflexes can participate in the more long-term and renin-angiotensin in short-term blood pressure control might be important to recognize in understanding mechanisms of hypertension.