Man reveals how an Apple Watch saved him from a life-threatening situation

Green tweeted on Friday that HeartWatch, one of the Apple Watch’s health sensors, measured his heart rate at consistently above his resting rate of 54, even though he was just sitting at his desk. Turns out those spikes were signaling a pulmonary embolism, his doctors told him after he made his way to the hospital, where they performed CT scans to reach their diagnosis, The Telegraph reports.

A pulmonary embolism occurs when a clot deep in your vein, most commonly in your leg, travels to your lungs from its original spot, blocking some or even all of your blood supply, according to the American Heart Association. This can prevent vital organs from getting the oxygen and blood they need to properly function, which can be fatal.

Thanks! Also wow! This is so fantastic that you are ok. Humbled to have played a part. Wishing you a rapid recovery & best of future health.

— HeartWatch (@HeartWatchApp) October 14, 2017

Green, a self-proclaimed “serial health tracker,” has experienced a pulmonary embolism before, meaning he had all the more reason to pay attention to what his heart is doing. While he suffers from generalized anxiety disorder, he told The Telegraph he was experiencing other symptoms during the time he received the heart rate alert, which pushed him to believe that he wasn’t experiencing a panic attack, but rather “something more.”