When the Series 4 was announced during an Apple event in September, the excitement didn’t center around a faster processor, larger screen and new watch faces. Instead, the big reveal was a new health feature, unlike anything that’s come before in a consumer wearable device. And while the new hardware was good-to-go when Apple released the watch later that month, the sophisticated health software wasn’t quite ready. But as of Thursday, the groundbreaking new feature that transforms your Apple Watch Series 4 into a true health monitor is ready for primetime.

The health benefits of wearable devices are real

The key feature in fitness trackers and many smartwatches is a focus on health. For years, they’ve been able to track your steps, running distance, the quality of your sleep and even keep tabs on your heart rate. That last feature alone has already helped save lives, as you can see from these reports we’ve covered over the past two years:

How a smartwatch saved a man’s lifeApple watch saves teen from kidney failureWow! App detects man’s heart issues and saves his lifeA FitBit saved this woman from heart failureThis simple gadget saved a man’s life. If you don’t have one, get one!

See what I mean? So the potential benefits aren’t just on paper, they’re proven. And now Apple has raised the bar. Bonus: Big insurance company will give you a free Apple Watch

A cut above the rest

Although the Apple Watch Series 4 looks similar to previous generations, it’s different in a big way. With Series 4, you can take an electrocardiogram (ECG or EKG) directly from your wrist. And it’s the first FDA-cleared ECG device offered directly to consumers over-the-counter. The new hardware has two built-in electrodes; one on the back of the watch and another on the digital crown. Along with the ECG app that installs with the latest OS update released Thursday, these features can help you detect signs of atrial fibrillation (AFib), which is the most common type of irregular heart rhythm. When activated, the new feature will work in the background to occasionally monitor for irregular heart rhythm. If an irregular rhythm is detected (such as a rapid heartbeat or a skipped beat), you’ll be notified, and that’s when it’s time to launch the ECG app. You’ll place your finger on the digital crown to complete the circuit and an ECG recording is taken. It takes about 30 seconds, then you’ll get one of three results: AFib (a problem), sinus rhythm (normal) or inconclusive. The data is stored on your phone and can be shared with your physician.

How to set up the new feature

If you have an Apple Watch Series 4, you’ll need to download and update to the latest watchOS, 5.1.2. Once up-and-running, you’ll still need to complete a number of forms regarding both new features. Bonus: This new Apple Watch feature could be a game-changer If you have a previous generation of Apple Watch, the updated watchOS will still look for irregular heart rhythms, but you will not have the ability to take an ECG from your device. IMPORTANT NOTE: The watch and app do not replace a doctor. As Apple states on their site, the ECG app and irregular heart rhythm notification features do NOT “detect a heart attack, blood clots, a stroke or other heart-related conditions including high blood pressure, congestive heart failure, high cholesterol or other forms of arrhythmia.” Read Apple’s official news release here. So if you think there’s a problem, even if your watch doesn’t detect an issue, seek medical help. In a recent episode of Consumer Tech Update, Kim discusses the Apple Watch Series 4 and its new features. Click or tap below to listen: