The Apple Watch packs in the most accurate wrist based heart rate monitor. That's according to the results of a study that put the smartwatch up against a host of other devices including ones from Fitbit and Mio.
The study, carried out by the Cleveland Clinic, involved hooking up 50 healthy adults to an EKG (electrocardiogram), a method of measuring heart rate activity by detecting the electrical activity produced by a heartbeat. This is still considered the most accurate way to record heart rate activity and is used by the medical industry and found inside heart rate monitor chest straps.
Read this: James' heart rate training diary
Testing it against the Fitbit Charge HR, Apple Watch, Mio Alpha, Intel's Basis Peak and a chest strap, it compared heart rate data at rest, when walking and jogging on a treadmill.
Unsurprisingly, the chest strap monitor came out on top, delivering a 99% accuracy in comparison to the EKG results. Next up was the Apple Watch with 90% accuracy as the other wearables tested dropped into the low 80s.
Another interesting finding that backs up a lot of what we've found in our own fitness tracking testing is that heart rate accuracy began to falter when workout intensity increased. "What we really noticed was all of the devices did not a bad job at rest for being accurate for their heart rate, but as the activity intensity went up, we saw more and more variability," said Dr. Gordon Blackburn, one of the study's authors and a director of cardiac rehabilitation at Cleveland Clinic.
Blackburn added, "At the higher levels of activity, some of the wrist technology was not accurate at all." He also spoke of the issues that wrist based heart rate monitors face alluding to the need to maintain contact with the sensors built into the likes of the Apple Watch and Fitbit's trackers. Quite simply, when you move more, you lose some of the contact and that can impact on the readings.
When we vigorously tested the heart rate tracking credentials of the Apple Watch Series 2 recently we were pleasantly surprised by how well it performed. We also know that there's other better performing wrist based monitors out there that weren't featured in this study like the TomTom Spark 3 for instance. But it still looks like the chest strap is king. For now...
Source: 9to5 Mac