Can Apple Watch measure blood pressure? Not yet—but here's how the science would work.
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.
This post, tries 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.