At a Glance: The Verdict
| Polar H9 | Garmin HRM-Pro Plus |
|---|---|
|
Best For: Gym and indoor training on a budget At $59.95 launch price, the H9 does the one job most people need: accurate heart rate sent to your watch, phone, or a gym machine. The 5kHz analog channel is the reason to pick it, since that is what older treadmills and pool-friendly gear still use. No running metrics, no memory, no bells. |
Best For: Garmin owners who run and want running dynamics The $129.99 HRM-Pro Plus adds an accelerometer for running dynamics and internal storage that saves your heart rate when your watch is out of range, then sends it over later. It is lighter, has a smaller strap module, and its battery is rated for about a year instead of a few months. |
Quick Buy Path
Check today’s pricing before you go deeper.
If these are already your two finalists, compare current pricing now, then keep reading for the full verdict.
Both of these are chest straps, and both will give you the electrical heart rate reading that wrist sensors keep guessing at. The gap between them is not accuracy. It is what happens with the data after your heart beats, and whether you need the extra sensor Garmin bolted on.
Key Differences
- Price: $59.95 for the Polar H9 versus $129.99 for the Garmin HRM-Pro Plus. That is more than double.
- Extra sensor: The HRM-Pro Plus has an accelerometer for running dynamics. The H9 is heart rate only.
- Storage: The Garmin stores heart rate internally and forwards it to your watch later. The Polar has no memory, so if the connection drops, the data is gone.
- Analog 5kHz: The H9 broadcasts on 5kHz in addition to Bluetooth and ANT+. The HRM-Pro Plus does not. That 5kHz channel is what older gym equipment and swim gear listen for.
- Battery: Polar rates the H9 at 400 hours, or about 16.7 days of active use. Garmin rates the HRM-Pro Plus at 8,760 hours, roughly 365 days.
- Water rating: Polar lists 30m. Garmin lists 5 ATM, which is the same 50m depth rating.
- Age: The H9 shipped in January 2020. The HRM-Pro Plus arrived in July 2022.
Deep Dive Comparison
Design & Comfort
Both use a plastic sensor module on a fabric strap, and both feel like nothing once the strap is set right. The Garmin module is smaller at 53.7mm compared to the Polar’s 65mm, and the whole unit weighs 52g against the Polar’s 60g. That 8g difference is not something you will feel mid-run, but the shorter module sits a little flatter under a tight compression shirt.
The real comfort question with any chest strap is strap fit, not module size. Both brands sell replacement straps, and both let you pop the sensor off to wash the band, which you should do often if you want the contacts to keep working.
Battery Life
This is the widest gap in the whole comparison. The Polar H9 is rated for 400 hours of use, which works out to about 16.7 days of continuous broadcasting. In practice that is roughly a year of five hour-long workouts a week before the CR2025 cell needs swapping. The Garmin HRM-Pro Plus is rated for 8,760 hours, or about 365 days, on its CR2032.
Neither strap has GPS, so there is no separate GPS battery figure for either one. Both use user-replaceable coin cells, so the fix is a $3 battery and a coin to twist the cover, not a service appointment.
Health & Fitness Features
Both straps measure heart rate the same way, by reading the electrical signal your heart puts out. That is why chest straps beat wrist optical sensors during intervals, cold weather starts, and anything with a lot of wrist flex like rowing or lifting. If pure heart rate accuracy is the goal, these two are close enough that the cheaper one wins.
The separation is the Garmin’s accelerometer, which feeds running dynamics: cadence, vertical oscillation, ground contact time, stride length, and the rest of the metrics Garmin Connect charts for you. It also means the strap can track pace and distance indoors on a treadmill without a foot pod. The Polar H9 has none of that. It reports heart rate and stops there.
The other Garmin advantage is store-and-forward. If you swim laps or leave your watch on the pool deck, the HRM-Pro Plus records heart rate to its own memory and uploads it once you are back in Bluetooth or ANT+ range. The H9 broadcasts live only. Lose the signal and that stretch of the workout is blank.
Smart Features
Neither of these is a smart device. No display, no music, no notifications, no NFC payments, no microphone or speaker. They are sensors, and that is the whole point.
What matters instead is what each one can talk to. The H9 does Bluetooth, ANT+, and 5kHz analog. That 5kHz channel is the one people overlook: it is the signal older treadmills, ellipticals, and some swim-capable devices use, and Garmin dropped it from the HRM-Pro Plus. If your gym’s cardio machines still show heart rate from a Polar strap, that is 5kHz doing the work. The HRM-Pro Plus is ANT+ and Bluetooth Low Energy only, which covers every modern watch, bike computer, Zwift setup, and phone app, but not that old gym hardware.
Price & Value
The H9 launched at $59.95 and the HRM-Pro Plus at $129.99, and both hold near those prices with occasional sales. You are paying $70 more for the Garmin, and the question is whether the accelerometer and the onboard memory are worth $70 to you.
For a runner already inside the Garmin ecosystem with a watch that displays running dynamics, yes. Those metrics only render properly on Garmin Connect and compatible watches, so the strap and the watch work as a pair. For a lifter, cyclist, spin class regular, or anyone who just wants a trustworthy heart rate number, the H9 delivers the same core reading for less than half the money.
Technical Specs
| Spec | Polar H9 | Garmin HRM-Pro Plus |
|---|---|---|
| Launch Price | $59.95 | $129.99 |
| Released | January 2020 | July 2022 |
| Module Size | 65 mm | 53.7 mm |
| Weight | 60 g | 52 g |
| Case Material | Plastic | Plastic |
| Water Rating | 30m | 5 ATM |
| Battery | 400 hours (16.7 days) | 8,760 hours (365 days) |
| Sensors | Heart Rate | Heart Rate, Accelerometer (Running Dynamics) |
| Connectivity | Bluetooth, ANT+, 5kHz | ANT+, Bluetooth Low Energy |
| Onboard Storage | None | Internal (store-and-forward) |
| Display | None | None |
The Verdict
The Polar H9 wins for most buyers. It costs $59.95, reads heart rate as accurately as any chest strap on the market, and its 5kHz analog broadcast reaches gym equipment the Garmin cannot talk to at all. Unless you specifically need running dynamics, you are spending $70 for a sensor you will never look at.
Buy the Polar H9 if you lift, cycle, take classes, use gym cardio machines, or own a non-Garmin watch and want reliable heart rate without paying for metrics you will not read. It is also the right pick for anyone whose training plan is built around heart rate zones and nothing else.
Buy the Garmin HRM-Pro Plus if you run seriously, own a Garmin watch that displays running dynamics, and want cadence, ground contact time, and vertical oscillation feeding into Garmin Connect. The store-and-forward memory seals it if you swim or ever train with the watch out of range. Outside that specific setup, the extra $70 buys you a battery you would not have replaced very often anyway.
Frequently Asked Questions
Is the Garmin HRM-Pro Plus more accurate than the Polar H9?
No. Both read the electrical signal from your heart, which is the accurate method, and neither has a meaningful edge on heart rate itself. The Garmin measures more things, but it does not measure heart rate better.
Will the Polar H9 work with a Garmin watch?
Yes. The H9 broadcasts on ANT+ and Bluetooth, so any Garmin watch will pair with it as a standard heart rate strap. You will get heart rate and heart rate zones, but no running dynamics, since the H9 has no accelerometer.
Why does the Polar H9 work with gym treadmills when the Garmin does not?
The H9 includes a 5kHz analog broadcast alongside Bluetooth and ANT+, and 5kHz is the signal older cardio equipment listens for. The HRM-Pro Plus only does ANT+ and Bluetooth Low Energy, so machines without a modern receiver will show nothing.
Is the HRM-Pro Plus worth $70 more than the H9?
Only if you run and own a Garmin watch that shows running dynamics. In that case the accelerometer data and the store-and-forward memory are real additions you will use every workout. For everyone else, the H9 delivers the same heart rate reading for less than half the price.
Which one should I get for swimming?
The Garmin HRM-Pro Plus, because it stores heart rate in memory and uploads it after the swim. Bluetooth and ANT+ do not travel through water, so the H9’s live-only broadcast leaves you with no pool data at all.
🏆 Ready to Decide?
Check the latest deals to see which one fits your budget.
Need a broader starting point first? Read Best Fitness Tracker (2026) for the fastest shortlist.
*We earn a commission if you make a purchase.
Specs and features may change. Always verify details on the manufacturer’s official site before purchasing.
