Hypertension is one of the leading causes of heart disease and stroke. As many as 45% of the US population suffers from high blood pressure, the proverbial “silent killer” being responsible for as many as 500,000 deaths in the US in 2018 alone. People with hypertension are encouraged to track their blood pressure regularly, yet the traditional arm-cuff tracker is plagued by measurement errors. FitBit is on a mission to offer a revolutionary way of measuring blood pressure - through its wearable smartwatch. In internal studies, FitBit found a correlation between pulse arrival time (PAT) - the time it takes for a pulse of blood to reach the wrist after a heartbeat - and blood pressure. FitBit wants to extend these early findings by running a month-long study with a broad population of FitBit users. If successful, FitBit will introduce a revolutionary method of seamless and accurate blood pressure tracking, overcoming the serious limitations of traditional at-home devices. The new method can lead to major health outcomes by early, accurate, and personalized blood pressure insights that will help define preventive interventions.