You're probably getting the idea by now: Before Basis felt comfortable claiming real-time, continuous heart-rate tracking, it needed a platform that could track blood flow through thick and thin, hell and highwater. So does the new Peak deliver? That's what I intended to find out. My control device was LG's Heart Rate Earphones set, which I've found to be accurate during A/B testing with a chest-strap heart-rate monitor.
The LG earphones match my chest-strap monitor beat for beat. They also keep heart rates locked during physical motion, and reliably respond to increasing and decreasing exertion levels. This is a very important point: During bursts of increased exertion, the LG earphones show faster heart rates in a logical, evenly scaled manner. And when I back off, the earphone's numbers scale down logically, as well. These LG earphones will never match the accuracy of a hospital ECG, but they're much more portable than an ECG, especially during spirited hikes up and down Mount Davidson, my testing playground.
Close, but not perfect tracking
There's no need to keep anyone in suspense: The Basis Peak did a reasonable job in matching the numbers reported by the earphones' smartphone app. Most of the time, the Peak was within 2 to 3 beats per minute of the earphones, and I found the two devices scaled pretty closely as I chugged my way up Mount Davidson as quickly as possible (and at a pace that still allowed me to record measurements on a notepad).
Ten minutes into the hike, the Peak displayed 133 bpm; the earphones, 131 bpm. Another 10 minutes later, the Peak showed 141 bpm; the earphones, 142 bpm. So far, so good--but then the Peak threw up some implausible readings as I kicked into overdrive getting close to the summit. The earphones were scaling evenly and logically with my increasing exertion levels, but for one reading the Peak actually slowed down, showing 145 bpm to the earphones 154 bpm.
It got worse when the Peak showed 129 bpm a brief time later. At this point, I was working even harder, and the earphones were reporting 165 bpm. But the glitch only lasted for a few moments. Finally, as I was steps away from the mountain's highest elevation, the Peak rapidly shot up, reporting 162 bpm to the earphones' 165 bpm. During my descent, the Peak returned to logical bpm levels, scaling evenly with the earphones.
Basis Peak versus Microsoft Band
So that was actually my second Mount Davidson hiking test. My first test, two days earlier, revealed similar performance. Every once in a while--twice during the first hike, once during the second--the Peak would show unusual (and untenable) heart-rate numbers. Then the band would correct itself, and return to reliable reporting.
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