The Apple Watch Ultra 3 is a powerful health and fitness watch; that much was evident from its predecessor, the Apple Watch Ultra 2 (otherwise known as the best Apple Watch, in terms of features and specs), and the specs shown off during last week’s big iPhone event.
The Apple Watch Ultra 3 packs 42 hours of battery life, the biggest and brightest screen on an Apple Watch yet, satellite connectivity, 5G, and Apple Watch’s powerful new software courtesy of watchOS 26. I finally have my hands on an Apple Watch Ultra 3 test unit, and I was very excited to put it to the test.
For my first test, I wanted to check the heart rate accuracy, the lynchpin of every wellness metric on even the best smartwatches. From sleep tracking to your Training Load, calorie burn estimations to the new hypertension detection, an accurate heart rate sensor and accompanying algorithm make all the difference.
To test it, I’m putting it against a Polar H10, perhaps the best heart rate monitor chest strap, in an accuracy test. Chest-mounted heart rate monitors in general, and the Polar H10 in particular, are considered the gold standard, used by fitness professionals to provide the most accurate heart rate information possible.
It uses electrical sensors positioned near the heart, just below the pectorals, in order to calculate heart rate more efficiently than LEDs at the wrist.
I cycled for 20 minutes on a stationary exercise bike, wearing the Apple Watch Ultra 3 and the Polar H10. I was also wearing a control watch on the other wrist, the Huawei Watch G6, which I’m also currently testing at the moment.
The results
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The results are very close together, as I expected, and not different enough to be statistically significant at this stage.
The Polar H10 estimated my average heart rate during the 20-minute cycling sprint session to be 147 bpm. It shows a steady rise up to Zone 5, before a minute’s worth of dip at the end, prior to me ending the session.
The other two graphs from Apple’s Fitness app and Huawei Health show the same pattern, and both the Apple Watch Ultra 3 and the Huawei Watch GT 6 (itself known for being very accurate in the heart rate stakes) show an average heart rate of 148, just 1 bpm off the chest-mounted sensor’s measurement.
The graphs also show virtually identical peaks and troughs, once you account for the fact that Apple’s heart rate graph stretches slightly as a result of its presentation in-app.
At this early stage, I’m happy that Apple’s heart rate sensor is up to snuff when compared with a chest-mounted heart rate strap, the industry standard.
Longer workouts might show further deviations, but given the way its predecessor performed against a top Garmin watch during the London marathon, I think that’s very unlikely.
