Pulse wave shape and artery stiffness

Flexible arteries give a sharp, fast upstroke and a reflected wave that arrives late. Stiffer arteries return the reflection sooner, rounding the wave.

What stiffens arteries

Ageing, high blood pressure, smoking, diabetes and high cholesterol. Regular exercise and blood pressure control can slow it.

How it is measured clinically

The reference method is carotid-femoral pulse wave velocity. Finger pulse sensors can estimate a stiffness index and reflection index from the wave shape.

What a camera can add

Camera signals are weaker and smoothed, so fine features blur. Pulselens shows your averaged beat and how much of it is spent rising, as an exploratory trend to compare with yourself over weeks.

Sources

• Allen J, Photoplethysmography and its application in clinical physiological measurement, Physiol Meas (2007)
• Charlton PH et al., Assessing hemodynamics from the photoplethysmogram (2018)