Enable High and Low Heart Rate Notifications
If your heart rate remains above or below a chosen beats per minute (BPM) while you appear to have been inactive for a period of 10 minutes, your Apple Watch can notify you.
Step 1 – You can enable heart rate notifications the first time you open the heart rate app on your Apple Watch, or at any time from the settings on your iPhone. Open the Apple Watch app on your iPhone now.
Step 2 – Tap the My Watch tab and then tap Heart. You can then set the high BPM rate and the low BPM rate. As a guide, normal heart rate for adults should be between 60 BPM at rest and 100 BPM when active, so these are good settings to begin with (you should seek medical advice if you believe these rates may not be normal for you).
Enable Irregular Rhythm Notifications
An Apple Watch series 1 (or later) can occasionally look at your heartbeat to check for an irregular rhythm that might be suggestive of atrial fibrillation (AFib). Here’s how to enable this feature.
Step 1 – As this feature might not be available on older version of iOS and WatchOS, you should make sure you have both updated. Then, on your iPhone, open the Health app.
Step 2 – Tap the Browse tab and look for the Heart section, where you can enable Irregular Rhythm Notifications. Once enabled, you can turn irregular rhythm notifications on or off in the Apple Watch app on your iPhone.
Step 3 – If you receive a notification, Apple Watch identified an irregular rhythm suggestive of AFib and confirmed it with multiple readings. It is then suggested that if you have not been diagnosed with AFib by a physician, you should talk to your doctor.
What is AFib?
According the American Heart Foundation, AFib is:
An irregular heartbeat or a condition in which the heart muscles fail to contract in a strong, rhythmic way. When a heart is in AFib, it may not be pumping enough oxygen-rich blood out to the body. A racing, pounding heartbeat that happens for no apparent reason should not be ignored, especially when other symptoms are also present, like shortness of breath with light physical activity or lightheadedness, dizziness, or unusual fatigue.