pulse pressure
Pulse pressure is the gap between the top and bottom blood pressure numbers—simply systolic minus diastolic. It captures how big the ‘swing’ of pressure is with each heartbeat, and it is literally what you feel when you take a pulse.
For a typical 120/80 reading, the pulse pressure is 40 mmHg. Its size is mainly set by two things: the stroke volume the heart ejects with each beat, and the stiffness (compliance) of the large arteries. A stiff aorta cannot expand to absorb the ejected blood, so the pressure spikes higher and falls lower, widening the pulse pressure.
A widening pulse pressure, especially in older adults, is a marker of arterial stiffening and carries cardiovascular risk; a very narrow pulse pressure can signal a low stroke volume, as in severe heart failure, blood loss or aortic stenosis. Like the other pressure numbers, it is interpreted in context—age, heart rate and the clinical picture all shape what a given value means.
An aging patient with 160/70 mmHg has a wide pulse pressure of 90, consistent with stiff, less elastic arteries.
Wide pulse pressure in the elderly is a common sign of arterial stiffening.
A widening pulse pressure usually reflects a stiffer aorta; a narrow one may reflect a fall in stroke volume.