The Withings Body-Cardio scale has many cool quantified self features. It passively logs data over WiFi, has excellent smartphone app integration for tracking progress and takes several measurements not typically seen in digital scales. Probably the most obscure of these measurements is the Pulse Wave Velocity number.
Pulse Wave Velocity is the easiest noninvasive way to determine arterial stiffness. Withings Body Cardio scale is measuring the time difference between blood ejection from the heart and the time it takes to reach the feet. A low speed is better as it is an indicator of low blood pressure and soft arteries.
Withings has conducted their own 111 person study to comparing their PWV with that coming from a medical grade sphygmocor which also measures PWV, but requires an experienced operator. When calculating PWV the Body-Cardio scale is using two technologies ballistocardiography (BCG) and impedance plethysmography (IPG).
I’ve been measuring my PWV since October and overall it has been quite stable in the 6’s which is near optimal for my age (40). I have seen diet play a bigger role than anything else. My PWV spikes when I carb up and massive drops occur when I keep the carbohydrate intake low.