Wearing a smartwatch isn’t just about receiving notifications from your smartphones these days, built-in fitness tracking features has played an essential role for users in keeping track of their health. James Green, a customer of the Apple Watch has just got his life saved by the HeartRate app, which suggested that he has an abnormally high heart rate though he was actually relaxing. After consulting with his doctor, he was diagnosed with pulmonary ebolism, a symptom where there’s a sudden blockage of a major blood vessel in the lung, and he obviously got the cure right after that.

The Apple Watch Series 1 and 2 didn’t have real-time heart monitoring unlike the recent Series 3, and its a wonder that the app has managed to alert Green on symptoms like that, it is something that many other fitness trackers can do. The HeartRate app takes advantage of the Apple Watch’s already available fitness tracking hardware, and it is able to track things such as steps, sleep and workouts. Looks like owning an Apple Watch isn’t too bad after all.