Zone 2 Coach turns any Bluetooth chest strap into a heart rate coach that talks back.

Most heart rate apps show you a number and leave you to police yourself. Zone 2 Coach watches the number for you and makes a noise the moment you drift out of your zone - so you can look at the road, the screen of a film, or nothing at all, and still train at the right intensity.

WHILE YOU TRAIN

- Out-of-zone alerts. A distinct tone when you go above your ceiling, a lower one when you drop below your floor, and a confirmation chime when you come back. Set a grace period so a single stray beat does not nag you.
- A separate hard ceiling. One threshold above your training zone that always sounds, whatever else is happening. Useful if you have a number you have decided not to cross.
- Alerts you can actually hear. They play on the alarm stream, so they cut through a fan, a treadmill or a pair of headphones, and they work with the phone on silent.
- It keeps running. A foreground service holds the strap connection with the screen off or the app in the background. The session does not stop because you switched apps, and there is no time limit on recording.
- Live trace, time in zone, distribution across below / in zone / above / ceiling, and training load in Banister TRIMP units weighted on your own heart rate reserve.
- HR drift - how much your heart rate climbs at the same effort between the start and end of the block. Under 5% the effort is genuinely aerobic.

AFTER YOU STOP

- Heart rate recovery measured automatically at 30, 60 and 120 seconds, with the recovery curve drawn out.
- Variability for the session: RMSSD, SDNN, pNN50, SD1, SD2 and a Poincare plot of every interval between beats.
- A full session summary, a symptom note and your session history.

All of the above is free, with no time limit and no ads.

ZONE 2 COACH PRO - ONE-TIME PURCHASE

A single in-app purchase unlocks Pro for good. No subscription. Your first 8 Readiness readings are free, so you can see your own baseline before you decide.

- Readiness. A guided three-minute resting reading, with the first minute discarded so your heart rate has time to settle, and an HRV score from 0 to 100. For the first seven readings it is an absolute scale; from the eighth it switches to YOUR OWN baseline - the mean and spread of your last sixty readings - so 50 is your normal day and the number finally means something. Baseline, seven-day trend, coefficient of variation and score history.
- Raw ECG recorder (Polar H10). Records the raw single-lead trace the strap streams at 130 Hz, straight to a CSV file you can open anywhere. It is a recorder, not an analyser: nothing is interpreted for you.
- CSV export. Beat-by-beat bpm and RR data for every session, your whole session history and your HRV readings, ready for a spreadsheet or to hand to someone.

WHAT YOU NEED

Any Bluetooth Low Energy heart rate strap using the standard heart rate profile - Polar, Garmin, Wahoo, Coospo, Magene and most others. A wrist optical sensor will not do: for variability you need beat-to-beat intervals a chest strap can actually deliver.

PRIVACY

No account. No analytics. No advertising. No server. Your training data stays on your phone and Zone 2 Coach sends it nowhere - put the phone in airplane mode and every training feature still works. The only part that talks to Google is Google Play's own billing system, and only for the optional Pro purchase.

Zone 2 Coach is training software. It is not a medical device, it does not diagnose anything, and it is not a substitute for medical advice.