Apple Watch saves woman's life by detecting blood clot.

A 29-year-old woman from Cincinnati credits her Apple Watch for saving her life after it alerted her to an irregular heartbeat while she was sleeping. After seeking medical attention, she was diagnosed with a saddle pulmonary embolism, which has a 50% fatality rate. The Apple Watch can measure heart rate throughout the day and recognize if it is elevated while the wearer is not active, potentially detecting life-threatening conditions.