Orthostatic hypotension 1: the physiology of blood pressure regulation

In response to certain situations, a series of actions take place in the body that can either raise or lower blood pressure. It is vital that nurses understand these actions and why they take place. This first article in a two-part series on orthostatic hypotension covers the anatomy, physiology and regulation of blood pressure; the second highlights how the condition is linked to falls, why it occurs, who is at risk and how it can be identified and managed.

This article has been double-blind peer reviewed

In this article…

• Anatomy and physiology of blood pressure

• Why regulating blood pressure is so important

• Factors that affect the functioning of the baroreceptor reflex

Key points

Blood pressure must be regulated - health problems occur if it is too high or too low

Blood pressure can adapt to changing needs, such as increasing when people are in ‘fight-or-flight’ mode, compensating during acute illness or decreasing at rest

The autonomic nervous system controls adjustments to blood pressure through the baroreceptor reflex

Certain illnesses or medications can compromise the functioning of the baroreceptor reflex

Orthostatic hypotension can occur if blood pressure does not adjust quickly enough after a sudden change in posture