Your watch set your Zone 2 from a formula. Your heart never read that formula.

Zone2AI builds your real Zone 2 heart rate range from your own data, scores every workout against it, and tells you your Fitness Age. Train in the right zone and the easy sessions finally do their job: more of your energy comes from fat, your aerobic engine grows, you get leaner, and your heart gets built for the long game. Train in the wrong one and you put in the hours without the payoff.

Most apps set Zone 2 from your age alone. That is a formula, not you. Zone2AI uses what your watch actually measured: your resting heart rate, your VO2 max and the highest heart rate you have really reached. The range keeps adjusting as you train and tell us how each session felt.

YOUR PERSONAL ZONE 2 RANGE
Built from your resting heart rate, VO2 max and true maximum heart rate. If a reading is missing, the app says so and uses a clearly labelled estimate until your watch provides one. You can always set the range yourself.

EVERY WORKOUT, ANALYZED
Each workout from your watch is scored on your phone: minutes in Zone 2, sprint minutes in Zone 5, average and peak heart rate, distance and calories. Sessions count toward your weekly goal, and a near miss still banks progress. Treadmill runs can be corrected to the console's distance, and the app learns from every correction.

FITNESS AGE
Your VO2 max and resting heart rate turn into a Fitness Age you can watch move over time, plus a plan built from your own numbers: Zone 2 consistency, sprints, resting heart rate, and supporting habits like strength work, sleep and HRV.

A COACH THAT READS YOUR DAY
A daily AI coach message that looks at your recent workouts, last night's sleep, your HRV and resting heart rate, and how much you moved, then tells you what today should look like. It observes, it never diagnoses.

ZONE 2 BUILDS THE ENGINE. SPRINTS RAISE THE CEILING.
Earn sprint credits through steady aerobic work, then spend them on the Norwegian 4x4 protocol: four minutes hard, three easy, four times.

WORKS WITH THE WATCH YOU ALREADY OWN
Samsung Galaxy Watch, Google Pixel Watch, Fitbit and other watches that write to Health Connect. Garmin connects directly, and Garmin owners can add our Connect IQ watch app for guided sprint sessions.

HOW ZONE2AI USES HEALTH CONNECT
Zone2AI only reads from Health Connect, and only what powers a feature you can see:
- Exercise sessions and heart rate: your workouts, their Zone 2 and Zone 5 minutes, and the top of your range.
- Resting heart rate and VO2 max: your range and your Fitness Age.
- Distance and active calories: the distance and calories on each workout, and treadmill corrections.
- Sleep, heart rate variability and steps: your Fitness Age plan and the coach's daily read.
- Weight and height: the BMI line of your Fitness Age plan, shown only outside the usual range and never as a target weight.
Readings are processed on your phone. When you open a coach insight, the numbers behind it are sent securely to our coaching service to write that one message; they are not stored and never used to train a model. Your data is never sold and never used for advertising. Nothing is ever written to Health Connect.

No account and no sign-in. Zone2AI is a training app, not a medical device.