Sunday race
In this weekly columnAndroid Central Wearables Editor Michael Hicks talks about the world of wearables, apps, and fitness tech related to running and health, in his quest to get faster and fitter.
Heart rate monitor chest straps have earned a reputation as the gold standard for workout accuracy. When it works as intended, my Polar H10 ECG delivers accurate and fast-adapting results, and I've used it in many reviews and accuracy tests against smartwatches to see how good their optical sensors are.
Despite all of that, I'm ready to leave chest straps behind, both professionally and personally.
My thoughts on this merged when I made a Galaxy Watch Ultra Accuracy TestSamsung promised a revamped optical sensor that would prevent light artifact issues during anaerobic workouts, so I tested the results with my COROS heart rate monitor, an optical heart rate bracelet.
Someone reposted the article on r/GalaxyWatch on Redditand the responses ranged from saying the test was “pretty useless” because I didn’t use a chest strap to “Trust Android Central to review a fitness device? LOL.” To paraphrase my childhood hero, Michael Jordan, I took it personally.
Why people trust chest strap heart rate monitors (and don't trust otocardiographs)
There is a widespread belief that optical heart rate straps cannot be trusted and that journalists using them for testing are wasting people's time. This is a reasonable belief, but one that needs to be debunked.
Any fitness smart watch The tracker, smart ring or bracelet uses LEDs to illuminate the skin and photodiodes to pick up the reflected light, allowing for visual tracking of changes in pulse. It is generally reliable, but prone to errors if the PPG sensors are not perfectly aligned; arm movement introduces gaps that let light and sweat through, distorting the results.
He Galaxy Watch Ultra and Pixel 3 watch Add more LEDs and new algorithms to try and solve the light artifact problem. Samsung and Google have a poor track record when it comes to support for external heart rate monitors, so I at least appreciate the effort, even if early tests suggest they have more work to do.
A chest strap avoids these problems with LEDs. It uses an electrocardiograph (ECG) to read the electrical rhythm of the heart muscle at its source rather than farther away, where changes in blood flow might take longer to register.
Since OHRs can Fight with precision on darker skin tones. —Some brands address this issue better than others—many athletes rely solely on chest straps.
That's not to say that a chest strap will magically give you perfect results every time. According to PolarYou must moisten the Polar H10 electrodes with water, gels or saliva (new) before sweat kicks in and improves the connection. Chest hair can block the signal, as can static from a synthetic T-shirt or other electrical sources. And you'll need a strap that's tight enough to maintain the connection.
But on top of that, they're also uncomfortable! I'm happy for people who have suffered from Stockholm syndrome and gotten used to the tightness of chest straps, but the restrictive feeling keeps me out of my running “zone.” I tolerated it (so far) because I wanted to provide readers with accurate test results.
Why do I use an OHR wristband to check accuracy?
A properly fitted OHR cuff on your biceps avoids the problems of a wrist sensor. You have much more surface area for the LEDs to read your pulse, it's more comfortable to fit, and there are no joints to bend and cause accidental separation during exercises like push-ups.
I received the COROS Heart Rate Monitor for a review and it gave accurate results. I gifted another COROS bracelet to my partner, who had had issues with the OHR on his wrist in the past due to skin tone, and so far he has not experienced the same issues with the strap on his arm.
At the time, I read the general consensus about chest strap supremacy and bought a Polar H10 to compare the two. Both gave me nearly identical results, but I decided to use the H10 for my smartwatch reviews because it was supposedly better.
I don't know if my H10 is a bit faulty, if I'm not moistening the electrodes enough, or if the strap isn't adjusted properly. But the more I use it, the more noticeable inaccuracies I have during the first 10-15 minutes of a workout.
I first realized this during my Garmin Forerunner 165 track test In March, the H10 HR briefly dipped from 152 to 138 bpm and held steady, while my Garmin, Coros, and Fitbit all spiked to 166 bpm. But it was just a minor blip (I thought).
Then, during my Accuracy test of Coros, Garmin and Polar watchesI saw some moments during a normal race. and A track workout where the heart rate shot way above or below all three watches before automatically correcting back to its usual perfection, without any adjustment on my part. This made judging the watch’s “best” heart rate harder when my ECG control group was off.
After those Redditors decided to come after me, I performed a simple COROS HRM vs. Polar H10 test, pairing the COROS with my Garmin Forerunner 965 and start a workout in the Polar Beat app simultaneously – you can see the results in the graphs above (a 10km run) and below (a challenging 1 mile track run).
I knew something was wrong during my first run, even with my phone in my pocket, because Polar Beat alternated between audio cues for “improving fitness” and “burning fat,” as if I was rapidly changing my heart rate and pace. It would simply lose and regain my actual heart rate signal before things would settle down, and it stayed perfect for over 30 minutes, without any physical adjustments on my part.
During the second test on the same day, the H10 immediately claimed I was close to max effort before even hitting a fast pace, then fluctuated slightly between too high and too low before catching up to my heart rate a few minutes later.
To avoid the inevitable comments, I'm not saying that all chest straps are inaccurate. I'm hoping to figure out why my H10 is having trouble at the beginning of its run. What's more important is the second half of each graph, where you'll see that Polar and COROS are almost on par.
They are never perfectly aligned. In the first run, every time I increased my pace or climbed a steep hill, COROS consistently fell behind by about 1 bpm before catching up to me and took a bit longer to register when I slowed down. During the second run, Polar registers small fluctuations of 1 bpm that COROS needs more time to detect.
But even chest strap lovers must admit that COROS' optical heart rate graph is spot on: it updates quickly and has fewer errors than wrist trackers.
Personally, the difference in accuracy is so minimal (and the difference in comfort is so wide) that I prefer to use my OHR cuff; even if it's not perfectIt's more than enough for Garmin or other brands to calculate my overall effort and training load. And it's much easier to forget I'm wearing an armband than a chest strap.
You are not understanding the point of these smartwatch accuracy tests
Yes, chest strap heart rate readings are more accurate than those from an optical sensor on your arm or wrist. Fitness experts like DC Rainmaker use chest straps as benchmarks for reviews for a reason. If you prioritize accuracy over comfort, buy a chest strap.
But here's what matters: smart watches are always I'm going to use optical readings and they are never It will be as good as the chest straps.
Why would I use a chest strap exclusively for accuracy testing when it's a quality standard that a watch can't reasonably match? Smartwatch heart rate accuracy has demonstrably improved across all brands in recent years, but if chest straps are the benchmark, then every watch I review is “inaccurate” to some degree.
You shouldn’t be reading smartwatch reviews that compare them to the standard of a chest-based ECG unless you’re looking for things to criticise. Instead, a more useful comparison is how its optical heart rate compares to a COROS HRM or Polar Verity Sense, which negate the usual issues with OHRs like light artefacts. Very few fitness watches come close to that standard, but some brands are using algorithms to try and close the gap.
It's not about perfection, it's about finding watches that are… good enough so you can compromise and leave the chest strap at home.
Comfortable and reliable
The COROS HRM is aimed at athletes who want something better than what a smartwatch's optical heart rate monitor can offer, but can't bring themselves to wear a chest strap. This hassle-free device works as soon as you put it on and stays on standby for up to 80 days once you take it off. It's comfortable, secure, and reliable.
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