| General | |
|---|---|
| Manufacturer | Fourth Frontier |
| Type | ECG-based chest strap heart rate monitor (general wellness product) |
| Series | Frontier |
| Released | 2026 |
| Price at launch | GBP |
| Predecessor | Frontier X2. See the Frontier X2 specifications. |
| Successor | Frontier X3 (US only). See the Frontier X3 specifications. |
| Weight | Around 10% lighter than the Frontier X2 |
Specifications and features as at launch.
Jump to: Expert opinion | What’s new | Specifications | Battery life | Features | Activity profiles | Further reading
Expert opinion
The Frontier Zone is the screen-free replacement for the X2, with the same ECG sensing and vibration alerts. Live ECG streaming and export sit behind Frontier Premium, where on the X2 they are included.
Battery life is around 30 days of typical use, and 7 days when recording 24 hours a day. At GBP 199 RRP (GBP 179 with code 5KRUNNER) it costs about a third of the X2’s GBP 579 RRP. It is sold on the UK and Europe store only, and the US store does not list it.
What’s new versus the Frontier X2
Hardware
- Typical battery life of around 30 days, up from around 14 days
- Continuous recording lasts 7 days, up from 24 hours
- USB-C charging, replacing micro USB
- Bluetooth 6.0, replacing Bluetooth 5.0
- Around 10% lighter
- No on-device screen
Software
- ECG streaming and export move behind Frontier Premium
Unchanged
- Single-lead ECG, IP67 water resistance and three simultaneous connections
- Heart rate, HRV, strain and breathing rate, plus vibration alerts, training load, Body Shock and step cadence
Specifications
| Physical | |
|---|---|
| Pod dimensions | 73.6 x 25.1 x 14mm |
| Weight | Around 10% lighter than the Frontier X2 (25g) |
| On-device screen | None |
| Water rating | IP67 |
| Charging | USB-C |
| Strap | Elasticated fabric with conductive and insulating layers, REACH and RoHS compliant, standard 45mm snap spacing |
| Sensing | |
| ECG lead | Single-lead ECG, approximating the V5 position of a 12-lead ECG |
| ECG sampling rate | Sampled at 125Hz, stored at 125Hz |
| Movement metrics | Body Shock and step cadence |
| Connectivity | |
| Bluetooth | Bluetooth 6.0 |
| ANT+ | Not supported |
| Simultaneous connections | Three: the app plus two external devices |
| Heart rate streaming to | Apple Watch, Garmin, Whoop, Peloton, Zwift and other BLE fitness devices |
| App connections | Apple Health or Health Connect, Strava and Garmin Connect (Garmin Connect requires Frontier Premium) |
| ECG access | |
| Viewing and exporting the ECG trace | Live streaming, and export as PDF, CSV or EDF, with Frontier Premium only |
| Subscription | |
| Frontier Premium adds | VO2 max, ventilatory thresholds, readiness score, sleep staging and Garmin Connect, plus ECG streaming |
| Regulatory | |
| Classification | General wellness product |
| FDA | Not a cleared medical device |
| Where to buy | Fourth Frontier UK and Europe store only |
Battery life
| Mode | Battery life |
|---|---|
| Typical use (about an hour a day) | Around 30 days |
| Recording continuously, 24 hours a day | 7 days |
Features
Feature explanations are covered in the relevant the5krunner heart rate hub. Features are listed under Fourth Frontier’s own headings.
Core capabilities
- 24/7 continuous ECG during 20+ activities
- VO2 max powered by HRV analytics
- Zone 2 training using VT1 to VT2 thresholds
- Personalised vibration alerts for every zone
Precision tracking features
- Heart rate from a chest-based ECG
- HRV insights (Fourth Frontier quotes a precision of 1ms)
- Tracks 20+ activities, including running, cycling, rowing and hiking
- VT1 to VT2 based zones
- VO2 max trends
- Zone-based vibration alerts
- Strain monitoring
- Training load
- Body Shock
- Session metrics: pace, distance and duration
- Activity tagging and notes
- ECG with GPS maps
- Readiness score
- Sleep stage analysis
- Stress monitoring
- Live ECG streaming and continuous recording
- ECG reports as PDF, CSV and EDF
Activity profiles
Fourth Frontier says the Zone tracks 20+ activities and names running, cycling, rowing and hiking. The manufacturer’s product page does not list the full set of activity profiles.
Further reading
Related straps
Looking at alternatives to the Frontier Zone?
- Predecessor: Fourth Frontier X2, with a colour display and ECG streaming included without a subscription.
- Also consider: the Polar H10. It is hardware only, so you need separate ECG software and it has none of the in-exercise features. It can record an ECG, which makes it competitive on that point.
