H9 Heart Rate Sensor

The strap sucks. If you have no lats, maybe it won't slide down your body as you run. But for those of us with big lats, you have to modify this thing. You can either modify the strap, or buy the $40 Polar Pro chest strap (you’ll have to replace any strap you get probably every 6-12 months so keep that in mind). I haven't tried the outrageously-priced Polar Pro but it's the only one on the market that has grips all the way around the strap, not just in the front. The chest strap can be easily modified as follows: Buy one of the "zig zag silicone grip wave bands" you can find online, and sew it (or use fabric glue or something) to the inside of your Polar chest strap and it actually stays in place while running! Just make sure you get the strap customized to your underchest first, and give yourself some space for the inevitable long-term loosening of the strap (you might need to tighten it gradually over time). Without the extra grip, you have to find the perfect balance through much trial and error between too tight and too loose. Too tight, and it creates a little cavity where the electrodes are between the strap and your chest (so it gives you terrible readings, if any). Too loose, and it falls down to your waist. I also found that using a small dab of electrode gel on each of the two electrodes on the back side of the chest strap (enough to cover just the two circles on the strap where the strap touches your chest) makes a huge difference in getting a consistent, accurate, read. Don't use water, it just doesn't work nearly as well. I love the Polar Beat app it comes with! It was the best free app I could find for Android for a heart rate monitor. I'm sure there are probably better paid ones out there but I didn't try any of them so can't attest. The Polar Beat app gives you a graph at the end of your workout that shows your heart rate over time, and tells you how many minutes and seconds you spent in each of the 5 heart rate zones (50%-60% of max heart rate = zone 1; 90-100% = zone 5). It has certain modes that track your GPS location for accurate maps of your runs/rides and the app will tell you every mile when running how long your mile took, your pace, and average heart rate. I've never used it for a bike ride. It also tracks calories very well and whenever it doesn't get an accurate read, it does a pretty good job "guessing" (better than the old Polar Watch I have). If I start my workout on the Polar app first, THEN start the workout on my Polar watch, it will let me use both to track my workouts which is great. That way I can leave my phone in my gym bag while running around the track, and use the watch instead to track % of max heart rate. It's also nice when using my phone for anything else while I'm doing a HIIT circuit or on the exercise bike, that way I can just look at my watch to see my stats. I don't have a smart watch so can't comment on how it works with that. I think you might need to get the latest and greatest to pair it to two or more smart devices at once. But this one works perfectly for one smart device and one dumb device.

I've only owned this for about 2 months now, with about 3 - 4 hours of intense sweat contact per week. But my impressions so far it's better than Garmin HRM Dual that lasted around 1.5 year with similar use pattern. The Garmin had noticeable corrosion on metal contacts, the metal buttons on strap was separating, would drop connections frequently towards end of life, and the ultimate failure points around screws on plastic unit seemed to be a silly design flaw. Unless the Garmin was a case of planned obsolescence, in which case kudos to that Garmin engineering team, it was an inferior product compared to the Polar. The Garmin failed because the thin plastic pieces beneath the tiny screw heads cracked and crumbled away so back cover could not hold battery in place. Seal was broken and the internals corroded to failure. All those weak points on the Garmin seem to be addressed on the Polar. In addition, the Polar actually pairs better with my Garmin products more quickly, consistently, and easily without having to wet the strap when I first put it on. Polar strap is a little narrower but for me its more comfortable because of softer elastic fabric. Minor downsides, the Polar strap loop and hook is not as robust and easy to use and narrower strap sometimes gets a little bunched up.

I had previously owned Garmin HRMs and only switched to Polar for Bluetooth connectivity with gym equipment, which Polar has and Garmin doesn’t. “Even a broken clock works twice a day”…that about sums it up with this Polar HRM. Worked for a couple of months but then started getting wildly inaccurate readings…if I was training at around 140 BPM, it would inexplicably spike and report 180 BPM and other times report something very low or even 0, as it it we’re disconnected. I did everything right: I used new 2025 batteries, dampened the strap before use, properly wore the strap snugly on the correct part of my chest, gently washed it with mild soap after each use, etc. Polar doesn’t have a customer service phone number that I could find, but I was able to find an email address. After a few back and forth emails — where I had to jump through hoops to troubleshoot the problem — they suggested I send both the strap and the sensor back to them for checking. A week or two later, I received a new sensor and a note that said the sensor had malfunctioned, so they replaced it. Rather than just simply send me a new kit, they returned my old strap. Ok, fine… A month or two later, the same thing happened again. I give up. I won’t buy another Polar product again. Despite its lack of Bluetooth connectivity to my gym’s equipment, I’m going back to Garmin. Garmin is more accurate, reliable, and has an actual customer service department.

I have been using this strap for over a year to monitor my heart rate on runs and bike rides, and it has worked flawlesly throughout. I've only changed the battery on it once during this time when I noticed that it would not connect to my bike computer. I personally have never had the band slip or shift off my chest. Once you pair it to your watch or bike computer, it's remarkably simple to use - just put it on and it automatically turns on and starts transmitting to whatever device you have. When you take it off, it automatically powers down. There is no on/off indicator light, but I found that it's not needed, and would likely just waste battery.

I use a heart rate monitor primarily for indoor and outdoor bike training so it must be reliable with consistent monitoring, durable through very sweaty sessions and comfortable enough to wear for long periods. Background This purchase was triggered because I was fed up with a competing brand's heart rate monitor which I've been using since 2019. That brand's data had been inconsistent over time, often dropping to 0, as well as needing 3 replacements from the manufacturer. I decided to switch to a different manufacturer and after much research decided to try the Polar H9. I didn't need the advanced features of the H10. I just needed it to pair with Zwift and my bicycle computer and be consistent. The setup The product was packed nicely and had minimal instructions. There was no real setup. I wet the strap contact points slightly, plugged in the monitor to the strap, adjusted the length and it was seen by Zwift immediately. Performance As of this review, I have been using it around 4 times a week for the past 3 months and the data has been very consistent. I will continue to review it as the competing brand was good at first and then degraded over time. The strap has been comfortable and easy enough to adjust. The monitor itself has had no issues with connectivity or water intrusion over this time. The only negative which is why I gave it 4 stars is that as you can see in the photos, where the strap meets the metal strap adjuster it is already starting to wear and you can see the elastic edge is wearing prematurely. I hand wash the strap with water and air dry it after every session so it is not from long-term salt exposure. I am concerned I will need to replace the strap once a year at this rate which can get expensive. Positives + Seems well made + Data has been solid over 3 months + Comfortable and easy to adjust + Water resistance seems to be consistent with claims + Easy to pair Negatives - Premature wear at the buckle point in the strap. Some fraying is noticeable at the edges. The elastic seems to be wearing prematurely even with consistent washing.

I was looking for a simple chest strap heart rate monitor to communicate with my Concept 2 RowERG rower (uses ANT+) and with my Amazfit T Rex 2 fitness watch (uses bluetooth). I wasn't sure if this could do both simultaneously, but decided to try it out. After a few minutes pairing things up in the POLAR phone app and registering it, I synced it to my watch and then connected to my rower monitor. Worked exactly as I hoped with no problems at all. I have plenty of other workout apps, so I don't use the available POLAR fitness app, but it appears to be fairly well designed for guiding workouts and tracking fitness. The H9 model is pretty basic in functionality, but it performs its job well. I've been using it 1.5 hours daily for a couple of weeks and the battery is still fine (which is expected). If any battery life issues crop up, I will update my review.

Used only once so far and it works just fine with my older Life Fitness T30 treadmill and the phone app. A bit more expensive than the new/old stock Polar T31 or T34 "sealed battery" sensors but still worth it since the H9's battery is replaceable and has additional tech features that are useful.

Update: I’ve tried using it and often it does work. Seems like there’s magic phone settings or magic pairing routine that makes it work. Problem is, I don’t know what it is. And it’s not documented. I raised my rating, nonetheless. Original review: I think it’s a useful product and strap is better than one I had a decade ago. But! It’s less than a year old, and has only been used 2-3 dozen times, and now sensor can’t always connect to app. So it’s effectively broken. (I did change battery recently— thinking problem was dead battery.) And app is a bit primitive. So I can’t recommend.