This Chest Strap Reads Your Heart Like an ECG, and the Battery Lasts Four Months
Most wrist trackers guess. This one reads your heart from your chest.
Wrist wearables read your pulse with light, and that gets shaky the second you start moving hard. Fourth Frontier just launched the Frontier X3, a chest-worn heart monitor that uses ECG-based sensing instead. It caught our eye, so our crew dug into the details, and it’s on our list to strap on for a few weeks of training. Here’s what we found.
What the Frontier X3 Is
A small chest-strap heart monitor (23 grams) that tracks your heart around the clock and during more than 20 kinds of workouts. It pairs with an app on iOS, Android and the web.
Standout Features
ECG-based sensing
Fourth Frontier says chest ECG stays accurate during intense exercise, where wrist sensors can drift.
Up to four months of battery
With about an hour of daily use. About 14 days if you wear it 24/7.
Deeper heart data
Heart rate, HRV, strain, breathing rate, VO₂ max, recovery and a cardiac age trend.
Lighter and faster to charge
10% lighter than the X2, USB-C charging that’s 50% faster, IP67 rated.
Low-risk to try
A 14-day money-back guarantee and a one-year warranty.
Who It’s For
Runners, cyclists and lifters who train by heart-rate zones, anyone who wants real recovery numbers, and guys keeping an eye on heart health who want more than a step count.
What We Want to Find Out
Is it comfortable enough to forget it’s there?
A chest strap only works if you wear it.
Do the insights change how you train?
Strain and recovery numbers are only useful if they’re clear.
Is the battery claim real?
Four months between charges would beat every watch we own.
Best for: runners, cyclists and lifters who train by heart-rate zones, and anyone who wants real recovery numbers
The perk: 30% off the launch with code LAUNCH30, plus a 14-day money-back guarantee
Caught our eye. A full crew review lands if we get one strapped on for a few weeks of training.
Some links in this post are affiliate links, so our crew may earn a small cut at no cost to you. Product details come from the brand.
More Gadget Finds
