As Inceptive Mind notes, the University of Toronto suggests using a technology known as transdermal optical imaging. It measures blood pressure by analyzing a short video with a person’s face. The method was tested on 1328 adults. Volunteers filmed themselves on the phone (clips for 2 minutes).
The system was able to measure three types of blood pressure with an accuracy of 95-96%. It uses optical sensors on a smartphone to pick up red light reflected from hemoglobin beneath the surface of the skin. This allows you to visualize and measure changes in blood flow.
A commercial application for Anura smartphones has been developed. It shows the level of stress and heart rate at rest based on the results of the video analysis. An application showing the level of pressure should enter the market this fall. The developers plan to expand the functionality of the application to measure blood sugar, hemoglobin and cholesterol.