Zone 2 AI: Vo2 Max & Endurance

Zone 2 AI: Vo2 Max & Endurance

Heart Rate Zones Training

105 ratings
29 reviews
Free
In-App PurchasesWith Ads

Details

  • Released
  • Updated
  • March 16, 2025
  • August 7, 2026

Features

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About

This app guides you through personalized Zone 2 and high-intensity sprint training protocols to improve mitochondrial efficiency and maximize VO2 Max. It offers real-time feedback, projects future health outcomes, and tracks your progress towards longevity goals.

Personalized Zone 2 training guidance
Norwegian 4x4 Sprint Protocol
Rate of Perceived Effort (RPE) feedback
Zone2AI Power Score calculation
Projected biological age and VO2 Max
Apple Watch haptic feedback
Syncs with Apple Health and other wearables
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+1

What's New in Zone 2 AI

2.4.3

August 7, 2026

Zone2AI keeps getting better: sharper zones, brighter celebrations. YOUR ZONES, EVEN SMARTER Your Zone 5 sprint threshold is now derived directly from your personal Zone 2 ceiling, keeping a healthy gap that scales with your own heart-rate reserve. Easy runs read as easy; sprints have to be earned. Past sessions re-score automatically — your history may get more accurate on its own. CELEBRATIONS, EVERY TIME Finish a valid Zone 2 session and the cinematic pyramid celebration now plays no matter how fast you close the workout summary — your moment waits for you. CLEARER GUIDANCE The zone guide now focuses on the two zones that drive your training — your calibrated Zone 2 and Zone 5 — and your progress screens always tell the difference between "still loading" and "not yet trained." PLUS Feedback you send from the app now always reaches us word-for-word, Garmin data handling got several reliability refinements, and Garmin users on older watch app versions get a friendly nudge to update.

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Subscription plans

Unlimited Access

Unlimited Access

$39.991 Year
Price Updates
August 5, 2026$39.99
January 16, 2026$17.99
August 6, 2025$8.99
May 10, 2025$19.99
May 3, 2025$19.99
April 4, 2025$14.99
How to cancel Zone 2 AI subscription ⁉️
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In-App Purchases

$79.99

Lifetime

Pay once. Pro access forever.

User reviews

Amazing App!

I was thrilled to find an app that was all about Zone 2 training. I wear a Garmin and tracking data definitely helps me stay motivated. This app is motivating and keeps me accountable and that’s exactly what a fitness app should do. The developer of this app cares about it working well. He is very responsive to questions. The app works seamlessly with my Garmin and I’m looking forward to any other perks he adds to it. Btw, since I have been using the app, my resting heart rate dropped and my hrv increased. Super happy!
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Response from developer

Kathleen, thank you. You did the training; we just kept score and nudged you to hold the zone. Zone 2 is the entire point of this app rather than one tab buried behind nine others, and Garmin is where most of our work goes. If anything ever looks off, email me and I will dig into it personally. Best, Rod. Founder of Zone2AI

So good

Takes the guess work out.

Response from developer

Thank you, this is exactly what we hoped to build: no guesswork, just train and trust it. I hope you enjoy every Zone 2 mile. Best, Rod.

Apple Watch Series 3

I have been saying to start targeting my heart health more. I life 5 days a week and I am I great fiscal shape but I know I need to working more on my heart health.

I have been hearing about Zone 2 triangle for some time and want to integrate that into my training program

I found the app last night and it seems to be perfect I downloaded it, set it up on my iPhone but it’s not on the Apple Watch.. now I know my series 3 is a bit old but I would assume it would work…

I tied to get help using the AI tool in the app and it does not work for helping with the app..

I searched in line and there’s little to now help.

I did find a posthaste app will not work on a series 3..

It seems to be more effort than it’s worth.. apps do not need to be this complicated.. it should be like any other app.. download set up then use..

I purchased the lifetime subscription for something it seems will not work.
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Response from developer

Hi Bill, thank you for the review, and for wanting to build the Zone 2 base. Helping people like you is why the app exists. Let me clear up the watch part, because the core of what you bought does work for you. The Zone2AI watch app needs a newer watchOS than the Series 3 can run, so it will not appear on that watch. That is a real limit of the older hardware, not something setup can fix. But you do not need our watch app to get your Zone 2 heart range and build your habit. Record your run or walk with the built-in Apple Workout app on your Series 3, then open Zone2AI on your iPhone. It reads that workout from Apple Health and gives you your time in Zone 2, the triangle, all of it. The in-app coach answers training questions, so for setup it is faster to email me directly at support@zone2ai.com and I will get you going personally. Best, Rod, Founder of Zone2AI

Many noticable glitches

The app freezes during mirroring in sprint session. It mentions the norwegian 4x4, but there is no clear way to log it. The coaching insights often give false info, as if a person hasn’t done a session. These are just a few things. It definitely needs to be revamped

Response from developer

Hi Amazinace, and thank you. This feedback makes the app better. I appreciate you taking the time to write it out. You flagged three real things, and I want to own each. A freeze during a sprint session is on us; the heaviest moment is right as an intense workout finishes and syncs in, and I want to find exactly where it is catching for you. You are also right that the Norwegian 4x4 is not as clear or as easy to start as it should be. We built that protocol carefully and have not yet brought it into every part of the experience, and making it obvious is on my to-do list. Finally, a coaching insight that reads as if you have not trained almost always means your latest session didn't sync on time, which we have been steadily fixing and clearly have not fully solved. I read every message myself. Tell me which watch you train with and I will get to the bottom of all three with you. Please email me at support@zone2ai.com. I want to earn those stars back. Best, Rod, Founder of Zone2AI

Has a lot of potential

Love the concept of this app, it’s just pretty buggy. It doesn’t accurately track your workouts, I’m primarily using this for the zone 2 heart rate indicator.

Response from developer

Hi Tim, thank you for the feedback, and for rooting for us. Love to hear that you like the core concept and the live Zone 2 indicator. You're right that workout tracking has had some bugs on some Garmin watches, but we've recently shipped a string of updates aimed at fixing exactly this. I'd love to get your specific setup tracking perfectly. Could you email me directly at support@zone2ai.com? I read every message and will work with you personally to get your data logging accurately every single time. I want to earn those extra stars! Best, Rod

Developer apps

FAQ

What does Zone 2 AI do?

Zone 2 AI provides a complete longevity protocol by combining steady-state Zone 2 training for mitochondrial efficiency with the Norwegian 4x4 Sprint Protocol to maximize VO2 Max. It offers personalized weekly prescriptions based on your biological data and validates your effort to project future health.

What are the key features of Zone 2 AI?

Key features include RPE feedback to improve heart rate ranges, the Sprint Protocol for VO2 Max enhancement, a Zone2AI Power Score to measure metabolic efficiency, future health projections, and incline calibration for treadmill training. It also offers true Zone 2 validation and Apple Watch haptics.

How much does Zone 2 AI cost?

The app is available for free with in-app purchases. Specific pricing details for premium features or subscriptions are not detailed in the provided description, but the core functionality is accessible.

What devices is Zone 2 AI compatible with?

Zone 2 AI works with Apple Watch and syncs with Apple Health. It also integrates with other popular fitness trackers like Polar, Garmin, Strava, and WHOOP, as long as they write workout data to Apple Health.

Who is Zone 2 AI for?

This app is designed for anyone seeking to build a consistent Zone 2 training habit, from beginners to high-performance individuals. It's ideal for biohackers, endurance athletes, and anyone optimizing for mitochondrial health and longevity.