By Stephen Pate – The Apple Watch is a great fitness wearable but it records wildly inaccurate heart rate readings.
As Apple tries to market the Watch for serious medical conditions like Atrial fibrillation, accuracy will become more important.
Does the Apple Watch heart rate inaccuracy matter? It does if you think its a medical device; otherwise, its just a consumer wearable that provides some information to help us keep active.
When Will Apple Fix The Scary Heart Readings on the Series 3 Watch
Over the past year I’ve learned how to fix the heart rate errors in Workouts. When that fails I just ignore the Apple Watch native readings and wear a Polar chest strap.
Why Heart Rate is key to the Apple Watch metrics
Apple promotes the Watch as a fitness device and heart rate is the key to everything. Heart rate is used to warn if your heart is beating erratically, too slow or too fast. It’s used to calculate active calories burned during Workouts and your recovery rate after workouts. For more on the Watch heart rate see Apple Support.
So many people have reported inaccurate heart rate readings on their Watch that Apple has walked back some of it’s claims. Apple admits the heart rate may not be accurate during workouts when your arms move such as Elliptical (stepper) or weight lifting.
Anyone with a heart condition will be concerned about their heart rate during and after exertion or exercise. I’ve had Watch readings above 200 BPM which is dangerous for my age: I’m not supposed to exercise continuously above 120 BPM. At first, readings above180 BPM freaked me out and I had to stop exercising.
Admittedly, both the Fitbit HR and Microsoft Band gave wonky readings as well.
How to fix your Apple Watch wild heart rate readings
The first thing to check is the Watch band fit. If your arms are moving during a workout, tighten the band snugly.
Make sure your arm is clean and don’t put the Watch on a tattoo.
Sometimes it helps to move the Watch higher on your wrist.
Try another Workout.
Try checking the Heart app to see if it’s lower. Switching from the Workout app to the Heart app and back can correct high readings. It seems like the Workout app is slow updating.
Connecting a chest strap to the Apple Watch
You can also use a chest strap with the Watch, since chest straps are more accurate. The Watch is measuring blood flow while the chest strap is measuring heart beats. I use a Polar H7 chest strap for indoor workouts and the Apple Watch readings will usually be close to it.
Apple Watch Bluetooth connection the Polar P7 chest strap in Watch Settings (Photo S. Pate)
Apple suggests you connect your chest strap to the Watch. “If you’re not able to get a consistent reading because of any of these factors, you can connect your Apple Watch wirelessly to external heart rate monitors such as Bluetooth chest straps. Learn how to pair Bluetooth accessories.”
Connect your chest strap on the Watch at Settings…Bluetooth…Health Devices.
It took a few tries to get the Polar P7 readings to show correctly on the Watch. Once connected the Watch heart rate only varied by 1 or 2 beats per minute from the Polar P7, the first time that happened.
Apple Watch connected to Polar P7 heart readings agrees with P7, shown next to the NuStep heart icon (Photo S. Pate)
During the 20 minute Stepper Workout in the photo below, the Watch agreed (93 BPM) with the Polar P7 (92 BPM – mid screen above time 12:18).
There were no high readings on the Watch except the Heart app said the highest rate was 98 BPM which did not show on the P7.
All in all, it’s disappointing the Watch can’t provide accurate readings and using 2 devices seems lame.
Update: If you decide to try connecting the chest strap, don’t forget to disconnect it from the Watch if you don’t want that setup.
Software bug when using chest strap
There’s a software bug when the chest strap is paired with the watch. The Workout will record but it won’t fill in the Workout ring. I reported this to Apple.
When a Polar P7 was Bluetooth connected to the Apple Watch Series 4, the heart rate readings stabilized and recorded the workout details but the Workout ring is missing the workout (Screenshot S. Pate)
Does it matter if the Apple Watch heart rates are wrong
If you believe the Apple Watch is a health device, it probably matters if the heart rate is grossly inaccurate. The Watch is supposed to warn you when your heart rate is too low or too high. Soon it will be predicting serious medical conditions like AF.
I learned that those readings are not worth paying attention to if I’m in a Workout.
This article applies to the Apple Watch Series 3 and 4. Series 4 is slightly more accurate than Series 3 from my experience.
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