From measuring your fitness goals to controlling your other Apple devices, the Apple Watch has myriad useful features for users in its newest iteration, including an FDA-approved heart rate monitoring app that can perform an electrocardiogram (ECG).
Note: To do an ECG reading, you need to have an Apple Watch Series 4, 5, or 6.
Here's how to set up the ECG app, measure your ECG, and read the ECG results.
What is an ECG?
According to the American Heart Association, an ECG "measures the electrical activity of the heartbeat" in order to detect whether a person's heart is beating at a healthy rhythm.
If the ECG measures a heartbeat that is too fast, too slow, or irregular, it could be an early sign of a heart condition.
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When administered at your doctor's office, an ECG looks at 12 areas of the heart to give a robust picture of its health, but Apple's ECG app focuses on only one.
Because of its narrow monitoring focus, Apple's ECG app is designed specifically to monitor for just one common heart condition: an irregular heartbeat called atrial fibrillation (AFib).
If left untreated, AFib can lead to blot clots, stroke, or heart failure.
How to set up ECG through your iPhone's Health app
Because the ECG app comes standard or as a software update for newer Apple Watches, setting up the app can be done simply by navigating through your iPhone's Health app. If not immediately prompted to set up the ECG, go to the Browse tab, then select Heart, choose Electrocardiograms (ECG), and finally tap Set Up ECG App to begin.
You'll be prompted to enter your birth date (the app is approved only for those 22 and over) and read through information about the ECG app, including best practice tips for taking your ECG reading, such as having your Apple Watch tight on your wrist and resting your arm on a table or on your leg for the reading.
You'll then be prompted to take a test ECG reading, or skip and wait to do so until after set-up.
How to take your ECG measurement on an Apple Watch
Once the ECG app is set up, a reading will take 30 seconds.
To do so, open the ECG app on your Apple Watch and press your finger to the watch's Digital Crown. For best results, Apple suggests resting your arm on a surface and ensuring that the back of your watch is dry and tight to the wrist.
After 30 seconds you'll receive one of four reading results and have the option to add and save symptoms to the reading.
Important: Should your reading be irregular or worrisome, you'll find an option to export your results as a PDF, which you could send directly to your doctor for a follow-up.
How to read your ECG results from an Apple Watch
After completing your ECG reading, your Apple Watch will give you one of four results: Sinus rhythm, atrial fibrillation, low or high heart rate, and inconclusive.
If your ECG reading is sinus rhythm then your watch has measured a heartbeat with a uniform rhythm between 50 and 100 BPM. This is considered normal, however if you receive this reading but are feeling unwell you should always follow up with your doctor.
If your ECG reading is atrial fibrillation (AFib) that means your watch has measured an irregular rhythm between 50 and 120 BPM. However, keep in mind that this reading is not a diagnosis of AFib and should be followed up with a visit to your doctor.
If your ECG reading is low or high heart rate then your watch has measured a heartbeat out of its range, either below 50 BPM or above 120 BPM.
This might sound alarming, but it doesn't necessarily mean anything is wrong. It is common to experience a low heart rate when sleeping, or as an extreme athlete, and a high heart rate can be attributed to stress or exercise.
However, as with the other results, follow up with your doctor if something doesn't seem right.
Finally, the last result that your ECG app could give you is inconclusive, meaning something went wrong when trying to measure your heartbeat.
This could be user error - maybe the back of your watch was sweaty or you didn't rest your arm when taking the measurement. It could also be inconclusive if you have a pacemaker or didn't create enough electrical signal for a sufficient reading.
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