# justzone2 — Zone 2 Training Made Simple > Indoor cycling app that automatically adjusts trainer resistance based on heart rate. (iPhone/iPad app by GEORGE GAIMES WHICHELOE.) - Source: https://appshunter.io/ios/app/justzone2/id6758547732 (this page in markdown: same URL + `.md`) - Developer: [GEORGE GAIMES WHICHELOE](https://appshunter.io/developer/1873551066) - Category: Health & Fitness - Price: $1.99 - Rating: 3.00/5 from 1 App Store ratings · 2 written reviews indexed - Age rating: 4+ - Requires: iOS 26.0 · 6 MB - Languages: American English - Released: 2026-09-23 - Data updated: 2026-11-09 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/justzone2/id6758547732/reviews.md ## What is justzone2? Most indoor cycling apps hold your power. JustZone2 holds your heart rate. Set your zone, start pedalling, and the app takes over. It reads your heart rate every second and continuously adjusts your trainer's resistance to keep you exactly where you meant to be — no watching the numbers, no reaching for the dial halfway through. Just the right effort, for the whole ride. ADAPTIVE ZONE TARGETING • A PID controller trims trainer resistance in real time to hold your heart rate in Zone 2 • You choose where you ride within Zone 2 — the upper part by default, where steady Zone 2 rides are meant to sit • Handles cardiac drift automatically — as you tire and your heart rate climbs, the power eases back to match • Optional warm-up and cool-down phases • Prefer to ride to a number? Run it as a straightforward fixed-power ERG session instead AND, WHEN YOU WANT IT, INTERVALS • An optional Interval Builder for your hard days, switched on in Settings • Set the number of intervals, their length and power, and the recovery power in between • Ride in sets, with a longer recovery between them, for sessions like Rønnestad's 3 × 13 × 30/15s • Ridden in ERG mode, with a countdown to every interval and the session's shape on screen • See each session's weighted average power, a better guide to how hard it will feel than plain average power • Interval rides upload to Strava under their own name and stay out of your Zone 2 progress charts WORKS WITH YOUR GEAR • Any smart trainer supporting the FTMS Bluetooth standard, including the Wahoo KICKR range • Heart rate from an Apple Watch, a Bluetooth chest strap, an optical arm band, or AirPods Pro 3 • Universal — iPhone, iPad and Apple Watch, with a Watch complication for a glance mid-ride YOUR DATA, WHERE YOU WANT IT • One-tap upload to Strava with power, heart rate, cadence, distance and calories • Saves to Apple Health as a full workout • Live Activity keeps your stats on the Lock Screen and in the Dynamic Island • Workout history with charts, so you can watch the aerobic base actually build BUILT TO GET OUT OF THE WAY • Large, readable metrics you can see from the bars • No ads, no upsells, nothing to sign up for • No subscription — one purchase, yours for good • Interrupted mid-session? It picks up exactly where you left off WHY ZONE 2 Easy aerobic work is what builds the engine: more mitochondria, more capillaries, better fat metabolism, and a foundation broad enough to carry everything you stack on top. It is the bulk of what elite endurance athletes actually do all year. Understanding that has never been the hard part. Holding the discipline to ride easy enough, for long enough, is the hard part — and that is precisely the bit JustZone2 takes off your hands. MADE FOR • Cyclists building an aerobic base through the winter • Athletes who want recovery days to stay genuinely easy • Anyone after structured indoor training without a games engine attached REQUIREMENTS A smart trainer that supports FTMS, and a heart-rate source — Apple Watch, chest strap, optical arm band or AirPods Pro 3. Set your zone once. Every ride after that, just press start. ## Key features - Adaptive Zone 2 heart rate targeting - Automatic cardiac drift adjustment - Optional interval training builder - Works with FTMS Bluetooth smart trainers - Heart rate monitoring from various devices - One-tap upload to Strava and Apple Health - Live Activity for Lock Screen stats ## Is justzone2 safe? Not enough ratings yet to assess justzone2. ## Is justzone2 legit? justzone2 has limited verification signals. The AppsHunter Legitimacy Score for justzone2 is 58 out of 100 points across 7 verification signals from App Store and developer data. ## Recent user reviews (2 of 2) All indexed reviews: https://appshunter.io/ios/app/justzone2/id6758547732/reviews.md ### 5/5 — Einfach, unkompliziert und funktioniert super! *2026-10-15* Die App macht genau das, was sie verspricht. Ich habe meinen Zwift Hub und meine Apple Watch (ebenfalls mit der App) verbunden, und alles hat super funktioniert, sogar im Hintergrund. Der große Pluspunkt ist das unkomplizierte Setup: Alles lässt sich direkt über das iPhone steuern. Kein zusätzlicher Bildschirm, Laptop oder Tisch neben dem Rollentrainer nötig. **Developer response:** Thanks for the feedback Floglin - glad you're enjoying the the app. Let me know if there's anything you'd like to to see in the app via https://www.justzone2.com ### 3/5 — Confused *2026-10-11* Not sure why there is a 60w adjustment zone at all. **Developer response:** Hi Mattweig - thanks for your question. The 60w adjustment zone is really there as a safety catch so that the power doesn't get too far from your preferred anchor that you set at the beginning. Would be very happy to discuss further if you get in touch via https://www.justzone2.com - there's a contact button at the bottom. If the 60w zone is too tight I can definitely add an option to remove it. Thanks again, George. ## Frequently asked questions about justzone2 ### What is justzone2? justzone2 is an indoor cycling app that automatically adjusts your smart trainer's resistance to keep your heart rate within Zone 2. It focuses on maintaining your target effort without manual adjustments. ### How does justzone2 keep my heart rate in Zone 2? The app uses a PID controller to continuously adjust your trainer's resistance in real-time, matching your heart rate to your desired Zone 2 target. It automatically compensates for cardiac drift. ### Can justzone2 be used for interval training? Yes, justzone2 includes an optional Interval Builder. You can set the number of intervals, their duration, and power targets, as well as recovery power, for structured hard workouts. ### What devices does justzone2 work with? justzone2 is compatible with any smart trainer supporting the FTMS Bluetooth standard. It can read heart rate from Apple Watch, Bluetooth chest straps, optical arm bands, and AirPods Pro 3. ### Does justzone2 have ads? No, justzone2 is ad-free. The app is designed to get out of the way and does not feature any advertisements or upsells. ### How much does justzone2 cost? justzone2 is a paid app, available for a one-time purchase of $1.99. There are no subscriptions or in-app purchases required after the initial buy. ### Can I upload my workouts from justzone2? Yes, justzone2 offers one-tap uploads to Strava, including data like power, heart rate, cadence, distance, and calories. It also saves workouts to Apple Health. ### What are the requirements for justzone2? To use justzone2, you need a smart trainer that supports the FTMS Bluetooth standard and a heart rate monitor. The app is available on iPhone, iPad, and Apple Watch. ## Version history (last 5 releases) ### 1.0.5 — 2026-10-21 • Calories: rides now save calories to Apple Health, calculated from your trainer's measured power, so they show in the Fitness app and count towards your Move ring. • Strava is optional, and the app now works fully without it: History charts the rides you record in the app, and the ride image saves to Photos at the end of each ride. • Brief heart-rate sensor dropouts (a reading far below your real heart rate) are filtered out, so they no longer upset the live display, Zone Targeting or your saved ride. • History: bubble size now shows how long each ride was. • A new look for the saved ride image. • Fixed: a "Recover Workout?" banner could appear after a ride that had finished normally. • Clearer messages if connecting to Strava doesn't work. ### 1.0.4 — 2026-10-04 • Fixed: with Warm Up on, Zone 2 sessions now rise to your target power when the warm-up ends. In versions 1.0.2 and 1.0.3 they could stay at the warm-up power. • Interval Builder: ride in sets. Repeat a block of intervals with a longer recovery between sets, for sessions like Rønnestad's 3 × 13 × 30/15s. • New interval sessions start with a 5-minute warm-up. • When a session finishes, your trainer eases to half your final power for the cool-down. ### 1.0.3 — 2026-10-02 • Interval Builder: every session now shows its weighted average power, a better guide to how hard it will feel than plain average power. It updates as you build the session and appears on your saved sessions, so you can compare them at a glance. • Small fixes and polish. ### 1.0.2 — 2026-09-30 • New: Interval Builder. JustZone2 can do more than Zone 2. Switch it on in Settings, build interval sessions (how many, how long, how hard, and the recovery in between) and ride them in ERG mode, with a countdown to every interval and a live view of where you are in the session. • Interval rides upload to Strava under their own name and stay out of your Zone 2 progress charts. • History charts now have clearer date labels that no longer repeat. • Small fixes and polish. ### 1.0.1 — 2026-09-26 • New Zone 2 Target setting: choose where you ride within Zone 2. Zone Targeting now holds you in the upper part of the zone by default, rather than its middle. • Zones screen: Zone 1 no longer shrinks to a thin sliver, and zone names keep their descriptions in landscape and on iPad. • History rows no longer wrap when you use a larger text size. • Demo Mode now shows its simulated trainer and heart-rate strap on the Workout screen. • Small fixes and polish. ## Apps similar to justzone2 | App | Rating | Price | Category | | --- | --- | --- | --- | | [RideByHeart](https://appshunter.io/ios/app/ridebyheart/id6754610795) | 4.7 (7) | Free | Health & Fitness | | [WristTopo: Maps for Watch](https://appshunter.io/ios/app/wristtopo-maps-for-watch/id6739765329) | 4.8 (95) | Free | Health & Fitness | | [JOIN Cycling Coach App](https://appshunter.io/ios/app/join-cycling-coach-app/id1167933055) | 4.7 (364) | Free | Health & Fitness | | [MIA Health](https://appshunter.io/ios/app/mia-health/id1658974043) | 4.8 (62) | Free | Health & Fitness | | [MoveSpring](https://appshunter.io/ios/app/movespring/id1315128138) | 3.8 (313) | Free | Health & Fitness | | [GYMKY - Fitness & AI Nutrition](https://appshunter.io/ios/app/gymky-fitness-and-ai-nutrition/id6470682855) | 5.0 (1) | Free | Health & Fitness | --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-09.*