London, May 20 : All thanks to technology and the human mind, one day 'hardware-laden undergarments' will be a necessity in every man's life. And the latest invention causing a 'shake' in this milieu is - blood pressure sensing underpants.
Blood pressure is not hard to measure, but the necessary equipment for clinically accurate measurements - a cuff, a pump, and stethoscope or electronics - is bulky and heavy.
However, researchers have recently found that a person's "pulse wave velocity" is closely linked to blood pressure. This is the rate at which the pulse pressure wave passes through the blood circulatory system, reports New Scientist.
Sensors sewn into the waistband of a person's underpants can measure the rate of this wave, consumer electronics company Philips has discovered, and could be used to calculate blood pressure for as long as the garment is worn.
Each sensor continually measures the electrical impedance of the tissue beneath it - a property that changes as the pulse wave passes by. A pair of such sensors can calculate the speed of the pulse wave by timing how long it takes to travel from one sensor to the other.
Once calibrated with a conventional blood-pressure reading, the electrodes can then give accurate blood-pressure readings, while the wearer enjoys the comfort of their own underpants.
The research team's invention is based on a polypropylene foam with piezoelectric properties that was discovered in 2004.
The plastic is flexible and has entirely different mechanical properties to most other, often crystalline or ceramic, piezoelectric materials. y adding silicone rubber to that material, Michael Yu at Johns Hopkins University in Baltimore and colleagues have made it possible to separately control the material's piezoelectric mechanical properties.