VO₂max training with AirPods Pro 3. No strap.
AirPods Pro 3 have a built-in optical heart-rate sensor — which means you can run proper heart-rate interval training with nothing but the earbuds you already wear. Stellar Intervals reads that heart rate live on iOS and runs the Norwegian 4×4 hands-free, with the interval cues right in your ears.
How it works
AirPods Pro 3 sense your heart rate optically from inside your ear. During a workout, iOS makes that reading available to apps through Apple Health (HealthKit). Stellar Intervals taps that live stream and uses it to drive the protocol — so the earbuds become your heart-rate monitor, your audio coach, and your music, all at once.
The full loop, with nothing strapped to your chest:
- Pop in your AirPods Pro 3 and open Stellar Intervals.
- Grant permission to read heart rate from Apple Health (once).
- Start a 4×4 — the timer counts each four-minute interval only while your heart rate is above 85% of max.
- Listen for the audible cues at every threshold crossing and interval change.
Why the ear is a good place to measure
Optical heart-rate accuracy depends a lot on where you measure. The ear is one of the better spots: it moves far less than the wrist during running and cycling, and it has steady blood flow close to the surface. For the kind of sustained, in-zone effort the 4×4 is built around, an ear sensor is a genuinely strong option.
Two practical tips for clean readings: use a snug ear-tip size so the sensor sits flush, and keep the tips clean. For all-out maximal sprints, a chest strap like the Polar H10 still edges ahead — but for VO₂max intervals, the AirPods are more than up to it.
Why pair it with a threshold-gated timer
Reading heart rate is only half the job — what you do with it is the point. A normal interval timer counts down four minutes the moment you press start, so the minute or two it takes to get your heart rate up is wasted “interval” time. Stellar Intervals is threshold-gated: the four-minute clock only runs while your AirPods report a heart rate above 85% of max, and pauses if you drop below. Every session is the same true dose — which is what makes your recovery trend worth tracking.
iOS only (for now)
AirPods Pro 3 heart rate reaches apps through HealthKit, which is an Apple framework — so this works on iPhone. On Android, Stellar Intervals reads heart rate from standard Bluetooth monitors instead: a Polar strap, a Garmin sensor, or any BLE heart-rate band.
Frequently asked questions
- Can AirPods Pro 3 measure heart rate?
Yes. AirPods Pro 3 include an optical heart-rate sensor in the ear tips. During workouts the heart-rate reading is available to iOS apps through Apple Health (HealthKit), so a training app can use it live — no chest strap or watch required.
- How accurate is the AirPods Pro 3 heart-rate sensor?
Ear-based optical sensing is well-suited to heart-rate measurement because the ear moves less than the wrist and has good blood flow. For steady and interval cardio it's a strong option. As with any optical sensor, a snug fit and clean tips give the most reliable readings; for maximal-effort sprint work a chest strap such as a Polar H10 remains the gold standard.
- How do I use AirPods Pro 3 for interval training?
Wear the AirPods, grant the app permission to read heart rate from Apple Health, and start your session. Stellar Intervals reads your live heart rate and runs the Norwegian 4×4 — counting the four-minute intervals only while you're above 85% of your max — entirely hands-free.
- Do I need an Apple Watch if I have AirPods Pro 3?
No. The AirPods Pro 3 optical sensor reports heart rate to iOS on its own, so you can train without a watch or a chest strap. The AirPods also give you the audible interval cues directly in your ears.
- Does AirPods Pro 3 heart rate work on Android?
Heart rate from AirPods Pro 3 is read through Apple HealthKit, which is iOS-only. On Android, use a Bluetooth heart-rate monitor such as a Polar strap or a Garmin sensor instead.
- Is my heart-rate data private?
Yes. Stellar Intervals reads live heart rate from AirPods Pro 3 via HealthKit only with your explicit permission. That HealthKit data is used in the moment for the workout and is not sent to our servers or used for advertising — see our privacy policy.
Train at VO₂max.
Pop in your AirPods Pro 3 and run a real 4×4 — heart-rate-gated, hands-free, no chest strap. iOS.