🔊 Real-Time Audio Zone Reminders • 100% Offline

Stay in Your Target Zone with Real-Time Audio Cues.

ZoneTrainer gives you instant voice reminders and audio alerts the moment you drop below or exceed your target heart rate zone. Train hands-free without looking at your phone.

09:41 BLE Connected
Zone 4 — Threshold
154 BPM
⚡ Voice Telemetry Active
Polar H10 Connected

Interactive Heart Rate Zone Calculator

Calculate your training zones instantly using Age, Karvonen (HRR), or Lactate Threshold (LTHR) formulas.

Engineered for Privacy & Performance

Everything you need for precise zone training without unnecessary cloud clutter.

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100% Offline & Private

Your heart rate and workout logs never leave your device. Zero accounts, zero tracking, zero external network requests.

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Universal BLE Support

Seamlessly pair with any standard Bluetooth Low Energy heart rate chest strap or optical arm sensor.

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Real-Time Audio Cues

Instant voice reminders and audio alerts whenever you enter, leave, or drift out of your target heart rate zone while running or cycling.

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Local Workout History

Store and review your past workout sessions, time spent in each zone, and heart rate trends stored safely in local Room database.

Supported Bluetooth Hardware

Compatible with standard GATT Heart Rate Service (0x180D) Bluetooth LE devices.

Polar
Polar H10, H9, Verity Sense

Industry-standard ECG chest straps & optical sensors verified for flawless BLE streaming.

Wahoo
Wahoo TICKR & TICKR X

Dual-band BLE heart rate monitors with instant pairing and high reliability.

Garmin
Garmin HRM-Dual & HRM-Pro

Premium chest strap monitors supporting standard Bluetooth HR profile.

Smartwatches & Armbands
BLE HR Broadcasting Devices

Compatible with Huawei Watch, Garmin, and any smartwatch or optical armband that broadcasts standard Bluetooth LE heart rate telemetry.