Credit: Brandon Butch

Phil Harrison, 30, took to Reddit to “say thanks to Apple.” In his original post, Harrison gave an account of how the Apple Watch nudged him to see a doctor while he was training for the Brighton Marathon — and how the wearable may very well have helped save his life.

The 30-year-old said that, although he was aware of some health issues in the past, he thought he was the healthiest he had ever been while he was training.

But, in early April, Harrison said he started getting heart palpitations that didn’t appear to stop. He happened to have an Apple Watch Series 4, which sports a consumer-facing electrocardiogram (ECG) sensor.

When he opened up the ECG app and ran a test, the app sent him a warning that it detected signs of atrial fibrillation and advised him to seek immediate medical attention.

Harrison added that a “series of events” lead him to go to accident and emergency (A&E) services, where he was told that he should not run in the closely approaching marathon. Now, two and a half months later, Harrison said he is about to undergo an open heart valve repair surgery in early July.

While he made sure to thank the doctors and nurses that were integral in his treatment, he added that his Apple Watch ultimately motivated him to seek medical attention.

“But I do know that without my Series 4 watch just giving me a little kick to get to A&E I may not be here today,” Harrison wrote on Reddit. “I would have done everything to run that marathon which most likely would have killed me.”

The ECG feature was first launched on the Apple Watch Series 4, but it was initially only released in the U.S. Since then, Apple has been continually rolling out the feature to new countries. The ECG feature was only available in the UK for a week when Harrison said he used it.

In addition to the Reddit post, Harrison said he also sent an email to Tim Cook and Craig Federighi. You can view a full list of where the ECG feature is available on Apple’s website.