Pulse Wave Analysis for blood pressure
There are many rumors that an upcoming Apple Watch will measure blood pressure; similar features exist on Samsung watches internationally and are likely to come to the US once cleared by the FDA.
In 2018, I helped run one of the first studies to show that health sensor data from wearables, when combined with a deep neural network, can pick up on signs of high blood pressure, sleep apnea, atrial fibrillation, and more. While the sensors have advanced in the last 7 years, the underlying science remains the same—and offers clues to the future.
In this post, I’ll try to explain the science behind blood pressure on the wrist (e.g., pulse wave velocity), past medical literature on using deep neural networks to glean signal from consumer wearables, likely limitations of wrist-based blood pressure, and how doctors and patients can incorporate it into medical practice.
When your heart beats, it sends a pressure wave—your pulse—throughout your body. As far back as antiquity, doctors could roughly sense blood pressure by pressing their finger against an artery. The first machine for measuring blood pressure, the sphygmograph, was invented in 1854. The modern modern blood pressure cuff, or sphygmomanometer, is its descendant.
