Frontier X2: One minute review
While the Polar H10 chest strap is used by athletes the world over as a heart rate monitor accuracy benchmark, one of its biggest pain points can be its connectivity issues. It’s hard to know whether it’s going to drop out, or you need to replace or clean the strap, until you actually start a workout. There’s also no interface or control on the heart rate monitor itself, and the app is cluttered and outdated. I like using the Polar H10 for its accuracy, but when it doesn’t work for me, it’s not always obvious until after the fact — which, when testing multiple devices simultaneously, is a frustrating experience. Frontier X2 from Fourth Frontier offers a different chest strap experience: a more modern app and a USB-chargeable device, with a screen and a button allowing you to manually start a workout and receive haptic feedback. That haptic feedback also triggers when you cross heart rate zone thresholds. While you can’t view the screen while wearing it on your chest of course, it does make workout preparation and phone connection so much easier than Polar’s offering. Guessing the heart rate monitor is working, even checking your phone to make sure heart rate is streaming correctly, only to have it drop out halfway through and lose my data due to a poor connection or crap strap, is an experience I’d like to leave in the past. The Frontier X2 uses heart rate information to calculate Whoop-style metrics like a Strain score, Stress score, Heart Rate Variability (HRV), Breathing Rate, and estimates calories burned. That last metric is somewhat outdated, as research from Stanford University found that calorie estimates based on heart rate are unreliable as they measure effort rather than energy expended. A premium tier subscription costs an additional $119. 99 / £109. 99 per year, adding a Readiness score, VO2 Max and even sleep stage analysis. As an already-expensive device, I wouldn’t recommend this unless you’re planning to make Frontier X2 your privacy fitness tracker, and accuracy is hyper-important to you. The continuous electrocardiogram, or ECG, can livestream an ECG scan for yourself or a medical professional to the Frontier app. Not only is this useful for spotting irregular heart rate rhythms over time, but I most often used it to check the HRM is streaming data correctly before starting working out in earnest, which is recommended, as the scan flags up in the app if there’s insufficient data due to poor connection. In terms of accuracy, I had no complaints. I took it for a test run against the Apple Watch Ultra 4 (which offers a redesigned Health Sensing System said to be ‘the most accurate ever on a wearable’) and the Garmin Fenix 9 Pro, which uses Garmin’s Elevate V5 that I’ve already tested against the Polar H10 and found to be very accurate. The results of the Frontier X2’s test run were excellent , with just 2 bpm separating the Frontier X2 from the Apple Watch Ultra 4 and Garmin Fenix 9 Pro’s average heart rate readings, a clear indication that all three devices are telling the same story about my body, and thus all three are very likely to be accurate…