H9 Heart Rate Sensor
Polar H9 Heart Rate Sensor is a chest strap from 2020, sitting in the budget band at an indicative $59.
It reads 4 of the 33 signals this comparison tracks. Nothing at all from sleep, fitness and body composition.
By sensor class: 3 at high accuracy and 1 at consumer grade. That grade is my classification of the hardware, not a lab test. Those readings come from ECG electrodes and an accelerometer.
Rated WR30 / 30m, fine for swimming. It weighs 21 g. No subscription is required.
Budget ECG chest strap; HR + R-R/HRV over BLE/ANT+, no onboard memory.
Key specs
What it tracks
Heart & vitals
Activity
Buying for battery life? See every device ranked by battery life
Turn a supported wearable into daily health scores
MyBodyAI reads Fitbit, Oura, Polar and Withings by logging in, and Garmin from a data export, then builds daily recovery, sleep, load and immune scores, a biological age estimate, and early warnings. Optional, and separate from this comparison.
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