Zone 2 AI: Vo2 Max & Endurance
Unbounded Technologies LLC Health & Fitness iPhoneiPod touchApple Watch
Zone 2 AI: Vo2 Max & Endurance is a free Health & Fitness app for iPhone and iPod touch by Unbounded Technologies LLC. Rated 4.5/5 from 132 ratings.
- Rating
- 4.5
- 132 ratings
- Price
- Free
- on the App Store
- Size
- 91 MB
- Age 4+
- Updated
- Oct 5
- 2026 · v2.6.9
Screenshots
About Zone 2 AI: Vo2 Max & Endurance
Build the Engine. Raise the Ceiling. Zone2AI is the complete longevity protocol. We combine steady-state Zone 2 training (to build mitochondrial efficiency) with the science-backed Norwegian 4x4 Sprint Protocol (to maximize VO2 Max). Whether you follow Peter Attia, Andrew Huberman, or Inigo San-Millán, you know that "exercise is the most potent longevity drug." Zone2AI is the only app that prescribes the exact dosage, validates your effort, and projects your future health. INTRODUCING ZONE2AI 2.0 - RPE Feedback: "Rate of Perceived Effort" after every workout, means that your Zone2Ai heart rate range gets better and better every time you use it. Finally, a Zone 2 training app that gets smarter every day. - The Sprint Protocol (Norwegian 4x4): Zone 2 builds the foundation; Sprints build the skyscraper. Earn "Sprint Credits" by completing your Zone 2 base, then redeem them for guided High-Intensity Interval Training (HIIT) designed to spike your VO2 Max. - Zone2AI Power Score: Are you becoming more metabolically efficient? We calculate your unique Power Score (Watts/kg) to measure exactly how much power your body can generate while remaining in a fat-burning state. - The Path (Future You): Don't just track today; visualize tomorrow. See how your current training trajectory impacts your predicted biological age and VO₂ Max over the next decade. - Incline Calibration: Training on a treadmill? Our new calibration tool helps you find the perfect incline to hit your metabolic peak without running. From "Restoration" to "Performance," choose the path that fits your biological reality. We build a custom weekly prescription based on your age, gender, and resting heart rate. CORE FEATURES - True Zone 2 Validation: We don't just log minutes. We filter your Apple Health data to find *actual* Zone 2 sessions: steady-state cardio in your personal biosignal range, sustained for as long as your personalized plan calls for. No false positives. - Apple Watch Haptics: Stay in the zone without looking at your wrist. Get subtle, real-time haptic feedback when you drift out of your target range during Zone 2 or Sprint sessions. - The Weekly Dose: Track your progress toward the ideal scientific benchmark of 180–240 minutes/week. - Total Privacy: No ads. No selling data. We use on-device logic and anonymized processing to generate your insights. Your biological data belongs to you. - Universal Sync: Works with your Apple Watch, Polar, Garmin, Strava, WHOOP: anything that writes workouts to Apple Health. Zone2AI is built for anyone seeking to build a real zone 2 habit. From beginners to high-performance individuals: biohackers, endurance athletes, and anyone optimizing for mitochondrial health and longevity. This is not a general fitness tracker. This is a precision tool for a longer life. Train in Zone 2. Sprint for VO2 Max. Defy your age. Zone2AI Pro (in-app purchase) is required to use the app beyond setup: a weekly or annual auto-renewing subscription, or a one-time lifetime purchase. Prices are shown in the app before you buy, and every feature described here is included in Pro. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & reviews
4.5
132 ratings
What’s new
Version 2.6.9 · Updated October 5, 2026
Your fitness age, and exactly what moves it. Open the Age tab: your number, poster size, with the trend from where you started to today and your VO2 max beside it. New underneath: Recommendations. A short, ranked list of what would make your number younger, built from your own data: Zone 2 minutes, sprints, resting heart rate, strength, sleep. The biggest lever sits on top. Tap any row and your coach explains it in your coach's voice. Three one-tap questions (sauna, alcohol, real food) fill in what your watch can't measure. Treadmill distance you can trust. At the end of an indoor run or walk, enter the number on the treadmill. That becomes your distance, and Zone2AI learns your watch: every time you enter it, the next guess gets closer. Treadmill workouts from other apps get the same row on iPhone. Every session explains itself. When a workout counts for less than you expected, it tells you why: minutes in your range, the range itself, and what counts. Tell it a session was a sprint or tennis and every screen, including your coach, judges it that way. Your sprint credits show exactly how they were earned and spent. On the watch: total time and distance first on the summary, and rides now record distance. One range scores everything, this week and every week before it. Two widgets put Fitness Age and VO2 max on your Home and Lock Screens. Outdoor sprints save as Outdoor Runs with their route. Settings, What You Told Us: every input behind your numbers, editable. Built for Apple Watch and Garmin.
App privacy
The developer, Unbounded Technologies LLC, reported these privacy practices to Apple.
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Purchases: Purchase History
- Identifiers: Device ID
Data Linked to You
The following data, which may be collected and linked to your identity, may be used for the following purposes:
- Purchases: Purchase History
Used for: Third-Party Advertising, Developer’s Advertising or Marketing, Analytics
Data Not Linked to You
The following data, which may be collected but is not linked to your identity, may be used for the following purposes:
- Identifiers: Device ID
- Usage Data: Product Interaction
- Health & Fitness: Fitness
Used for: Developer’s Advertising or Marketing, Analytics, Product Personalization
Alternatives to Zone 2 AI: Vo2 Max & Endurance
Looking for apps like Zone 2 AI: Vo2 Max & Endurance? Here are 6 similar apps on the App Store. The highest rated is HYBRD: Get Stronger & Faster (4.8/5), and all 6 are free to download.
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Zone 2: Heart Rate Training
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Zone Trainer: Heart Rate Zones
4.7
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VO2 Max Pro: Track Fitness Age
4.4
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HYBRD: Get Stronger & Faster
4.8
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VO2Max Training
4.5
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Perform: Fitness, Health, HRV
4.3
| App | Rating | Price | Last updated | Compare |
|---|---|---|---|---|
| Zone 2 AI: Vo2 Max & Endurance | 4.5 / 5 (132 ratings) | Free | October 5, 2026 | |
| Zone 2: Heart Rate Training | 4.6 / 5 (243) | Free | Sep 10, 2026 | Compare |
| Zone Trainer: Heart Rate Zones | 4.7 / 5 (18) | Free | Oct 7, 2026 | Compare |
| VO2 Max Pro: Track Fitness Age | 4.4 / 5 (56) | Free | Oct 7, 2026 | Compare |
| HYBRD: Get Stronger & Faster | 4.8 / 5 (766) | Free | Sep 24, 2026 | Compare |
| VO2Max Training | 4.5 / 5 (8) | Free | Sep 20, 2026 | Compare |
| Perform: Fitness, Health, HRV | 4.3 / 5 (34) | Free | Sep 7, 2026 | Compare |