Polar OH1+ Review (2019 ANT+ Update) | Arm-Worn Optical HR Sensor

FTC: Affiliate Disclosure: All links pay commissionReading Time: 22 minutes

Polar OH1+ Review

This Polar OH1+ Rseview (2019 Update) will look in detail at Polar’s updated, arm-worn optical heart rate monitor that supports just about every sport and almost every app and sport watch using BLE and ANT+ as well as caching your HR data from swims.



When the OH1 was first announced I was excited. With the announcement of the OH1+ supporting ANT+ in 2019, I was just that little bit more excited.

In my opinion, Polar have pressed quite a few tasty sports marketing buttons with the OH1+; it sells well for a variety of sports uses which I have previously covered in more detail here (link to:

This is the 2019 update to an earlier 2017 review

Both old and new images are shown

In Brief
  • Price - 91%
  • Apparent Accuracy - 94%
  • Build Quality & Design - 95%
  • Feafures, Including App - 96%
  • Openness & Compatability - 99%


The Polar OH1+ optical heart rate monitor is just about as good as can get for the vast majority of people in the vast majority of sports using most recent apps and sports watches.

It probably is the best HRM in this category.

To balance that praise and RECOMMENDATION, bear in mind that the battery life of 12 hours is not as good as the competing TICKR FIT and that’s the one main aspect of the OH1 that could be sensibly improved. The OH1+’s strap could perhaps also be a bit wider.



  • Supports BLE and ANT+ – hence most apps and most sports watches
  • Caches Data so suitable for gym use, team sports and swimming
  • Two ways to use it for swimming – armband or goggle clip
  • Decent battery life
  • Small format
  • Reliable
  • Mostly Accurate when worn on the arm


  • Narrow strap
  • Battery life
  • Slightly fiddly button


It’s a Bluetooth SMART (BLE) and ANT+ optical Heart Rate (HR) monitor (oHRM) intended to be worn on the arm.

You can pair it with apps and sports watches as you would do any other Bluetooth SMART or ANT+ heart rate monitor. Most modern sports watches and apps are compatible with the OH1.


It’s ALSO waterproof and it can record and store (cache) HR data to be retrieved later – ideal for swimming.

The Polar OH1+ is similar to the Scosche RHYTHM+ product (Reviewed, link to but the Polar OH1+ also caches data, is waterproof and has superior battery life. From other reports, I am not convinced that the newer Scosche RHYTHM24 is stable enough for me to review or for you to buy.

The Polar OH1+ is also similar to the Wahoo TICKR FIT product (Reviewed, link to but the TICKR FIT is physically larger, not waterproof for swimming and does not cache data. Then again, the TICKR FIT does have better battery life.


You can use this device in one of these ways:

  1. As a Bluetooth heart rate monitor, just as you would with a chest strap….but on your arm; AND
  2. As an ANT+ heart rate monitor, just as you would with a chest strap….but on your arm; AND
  3. As a CACHING heart rate monitor linking and syncing later ONLY to Polar BEAT/FLOW; or
  4. Those three ways simultaneously, effectively allowing the creation of multiple separate, identical workouts; or
  5. As a CACHING heart rate monitor for swimming by clipping to your goggles (FORM Goggles will display live swimming HR )


A: Me! I use it regularly.

Polar’s marketing is focussed on swimming, gym use, cycling and ‘general’ sports use. Just as it should. The Polar OH1+ is great for sports that require: a safe, comfortable wear-position; a separation of the recording device from the sensor; and/or waterproofing. 2 years after the original version’s release and I still use my OH1 as one source of HR when testing new running sports watches.

Those features thus nicely cover these sports: swimming; open water swimming; team sports; gym classes; cycling; running; any regular sport where you just don’t want to wear a chest strap; and 24×7 HR tracking.

*IF* it’s accurate then many people could switch to it.

Let’s not get ahead of ourselves. The accuracy stats will follow further below, so let’s start off this Polar OH1+ Review with a bit more detail on the Polar OH1+ itself.


I’ll keep this brief. You get a box; the strap; the sensor; a charging cradle; a swim clip; and, of course, lots of bits of paper that you will never, ever read.


The circular pod has all the clever stuff inside it. The strap just holds the pod in place against the skin on the arm (or wherever you put it).

To charge the OH1+, the proprietary cradle is required and there is no other alternative to it – don’t lose it. That cradle will plug into any standard USB port – for example in a wall socket port or in a computer. When mounted into horizontal computer ports it might be tricky to use adjacent ports and vertical ports are better – as shown below.

Either way, you could buy a £/$/Eu2.00 USB extension cable which would negate any issues with nearby dongles.


The stated battery life of 12 hours is approximately correct. I have got somewhere between 11.5 and 12 hours of mixed broadcasting-only and broadcasting+caching usage on a single, full charge. After 2 years of use of the original version, that battery life did deteriorate to around 8-9 hours however the annoying thing was that the battery would discharge slowly even when turned off to the point where a week or two later the battery was flat. I don’t know if that will still happen on the newer OH1+ model.

Polar do say that you will not notice any degradation in life until after at least 300 full charges.

Polar have also specifically confimed to me that battery discharge when ‘off’ has been improved in the OH1+

It is likely that caching and use in different sports will make little, or no, difference at all to the 12 hours of battery life. It only has one job to do. However with the ANT+ channel also broadcasting then that could slightly impact on the battery life (you can disable ANT+ in the Polar BEAT app)

In caching mode the ‘battery low’ warning message appears about 2 HOURS prior to total depletion of the battery. The LED flashes change to include RED.


The biggest danger to the battery life is forgetting to turn the OH1 off !

This Polar OH1+ review will now turn to the performance characteristics of the product.


The OH1+ is super small (dia 29.85mm x 9.5mm high) and super light (5g sensor + 12g armband). to put that into a real-world context here are some comparisons to an AAA and AA battery, the ones most of us use all over the world, although probably with different names. You know the ones I mean.

This ruler might help even more 😉 as well as a penny/cent.

IT’S SMALL. Perhaps not ‘tiny’. Here it is compared to the SCOSCHE RHYTHM+ which, by comparison, looks like a bit of a beast.

The pod is even smaller than the Suunto HRM pod and Polar’s relatively new H10 chest strap. Polar H10 reviewed here.

But the OH1+’s sensor looks like the exact same 6-LED sensor used in Polar’s recent higher-end watches, the M430 and M600

However this is not Polar’s latest HR technology, the latest is PRECISION PRIME, which is found in the Polar Vantage series of high-end wrist-watches.


No special setup is required. Just pair the Polar OH1+ to your device(s).

The rest of this section is mostly for those of  you who like to play a bit more with the tech!

Setting up the Polar OH1+ will involve pairing it to the Polar BEAT app and then to other apps, or devices, of your choice.


You may be asked to update the firmware, which is automatic and takes 10-20 minutes.

Consider the Polar BEAT app as the ‘maintenance’ app which also records workouts for those of you chosing not to use a watch. Then the FLOW app is used to view your detailed stats.


3rd party apps may subtly pair to the OH1+ in different ways. I paired to all the following apps to at least prove to myself that they displayed my heart rate: Polar Beat; WAHOO Fitness; and STRAVA.

If you simultaneously try to pair to more than one OPEN app on your smartphone the last app you try won’t work. Fully close the apps.

Here it is paired and working in Polar BEAT.

And similarly, here it is paired and working in the WAHOO Fitness app

Polar does not specifically state which apps the OH1+ is compatible with. It’s likely to be a long list.


The initial pairing of the OH1+ to any new BLE device seemed to take several 10s of seconds. If you just leave it, the BLE pairing figures itself out, unless actively paired elsewhere. In that latter case you will NOT be able to pair it to a new BLE device.

ANT+ connections were MUCH more quickly established and you can have an unlimited number of those connections – as well as your single BLE connection as well as a cached version.

Firstly I proved to myself that I could simultaneously pair over both BLE and ANT+…like this.

I also tested pairing separately with several of Polar’s devices as well as to a Suunto SPARTAN, a WAHOO bike computer and several apps via an Android smartphone. Everything I tried worked. Indeed any modern device that supports Bluetooth SMART should work and that includes newer, high-end Garmins. So as a broad guide to you, pretty much everything SHOULD work with the OH1.

You might have problems with how some smartphone manufacturers implement earlier versions of Android and there could be other vagaries. Polar haven’t tested all of the thousands of combinations and neither have I. Sorry.

Points on pairing

  1. You can store the BLE pairing of your OH1+ simultaneously on lots of devices and/or simultaneously in lots of apps. HOWEVER only one of those BLE pairings can be active. So if you have Polar BEAT open then you will NOT be able to pair to ANYTHING else with BLE. Fully close Polar BEAT (or whatever active app is open)
  2. If your device appears to have suddenly stopped working then there’s a good chance your smartphone in the next room is the cause of your problems 😉 ie the smartphone+app is actively paired to your OH1. That’s Bluetooth SMART for you…Polar can’t change that.
  3. If Polar FLOW is synchronising the OH1+ in the background then you will not be able to pair or connect to your OH1+.
  4. If you use many smartphone apps on a smartphone then you have to pair the OH1 with every app. i.e. you do NOT pair it with the smartphone, you pair it WITHIN the app. Every app. It will only work with one at once.
  5. You have unlimited ANT+ connections available.


This Polar OH1+ Review will now cover general usage considerations before going on to look at how to start, stop and cache your workout.


Polar does not specifically recommend wearing the OH1+ on the wrist but it will work there. The upper arm or the upper part of the lower forearm WILL give superior results and be more comfortable. However, there is no reason at all why you couldn’t wear it anywhere else; you will even get a reading if you hold the sensor against your thumb.

You would typically wear it with the Polar OH1+ sensor on the OUTSIDE of the upper arm – that’s what I do.

I found the adjustable strap to be relatively comfortable. You will see later that I got good accuracy results and there was no need to have the strap fastened tightly.

It is one continuous elasticated strap and there is no clasp to unbuckle. You just slide it up your arm into position and ensure it is tight enough. This probably takes 5 seconds and there’s no reason why you could not do that in a leisurely triathlon in T1 after the swim – you could wear it under your wetsuit of course.

The GREEN LEDs clearly indicate the mode the Polar OH1+ is on. If you don’t wear the OH1 the ‘right way’ around then you won’t be able to see the LED when it’s on your arm. ie point the GREEN LED upwards towards your eyes.

It can be worn under a wetsuit. My wetsuit is relatively thin and I would suggest you take a degree of care when getting into and out of your wetsuit. I did wear it under a wetsuit, everything WAS good but I would NOT recommend it for regular usage. Eventually, you will rip your expensive wetsuit.


The new clip for swim goggles generally works better than the original armband for swimming. It’s definitely a welcomed innovation from Polar.

The armband DOES still work whilst swimming but can sometimes might ‘flip’ over. Using the clip to secure the Polar OH1+ to your goggles, as shown below, works reliably and unobtrusively. You will press the silver button TWICE to start caching and the small LED will then quickly flash green TWICE to confirm it is caching.

The only issue I found with the new swim clip is that I had to half-tuck it under my swim cap.


You might also want to consider these general usage points:

Polar OH1 Transmitting underwater – note the bubbles


A short, single button press turns the OH1 on. If you’ve already paired it to another watch or app then you are good to go.

Next, you can press the button twice to enable cached recording on the OH1.

A long button press turns it off.

A later section looks at the various LED colours/flashes in detail, some of which you may want to familiarise yourself with over time to ensure that the OH1 is doing what you think it is.


Cached data can be sent to Polar FLOW in one of two ways.

Firstly, with the Polar OH1+ turned back on after you have stopped recording then all you have to do is start the Polar FLOW/BEAT APP on your smartphone and your workout will be sent to FLOW in the background on both your smartphone and online. The blue light on the OH1+ will flash and your smartphone will probably display two arrows going round in a circle on the top status bar, or similar, as shown below. You will probably also get the message “Polar Flow is syncing” in your notifications, or the Polar BEAT app might say that the OH1+ is connected to another device (once syncing is complete it WILL connect).

Even if the OH1+ is turned off, when charging the OH1+ on your computer the sync’d data will automatically be copied to FLOW with the Polar FLOW SYNC software, if installed. FLOWSYNC will tell you how many cached sessions it has just sent to FLOW.



The speed of synchronisation will depend on many factors such as a number of sessions to be sync’d; duration of sessions to be sync’d; whether you use the FLOW app or FLOW SYNC; the speed of your Bluetooth/wifi/internet connections. To generalise the speed of syncing on the app, I would say it will take tens of seconds or up to minute, or so, rather than minutes or tens of minutes. It’s relatively quick but certainly not instant on a smartphone.

Synchronisation via Polar Flow Sync on your computer takes seconds and is much quicker than Flow Sync with Polar’s watches.

During synchronisation, the time and date will be set on the Polar OH1+. There could be quite a few scenarios where the time used for cached data is a few seconds out from the exact, correct time. When comparing to other devices I sometimes had discrepancies of start times by over a minute, which I was not expecting.

When using cached data it is always assigned to the ‘Other Indoor’ sport profile by default. This default sport setting that is used to create a workout file cannot be changed but the sport can later be manually changed in FLOW after your specific workout has been sync’d to FLOW.

Change the sport type in Polar FLOW here

When paired to a watch or used in an app, no sport profile is activated on the OH1, it just records. The sports profile used on the watch which is totally independent of the OH1+. However, if you enable recording/caching then the ‘other indoor’ profile will be used for the recorded/cached workout regardless of what may be happening simultaneously on a paired Polar sports watch…confused yet? 🙂

When all the syncing is done you will probably have duplicate files on FLOW and I do not think you can merge them easily. There are ways to do it outside of FLOW – all of them too convoluted to perform regularly.


This is one of those ‘heads-up’ sections. Especially for those of you with experience of how other vendors implement caching.

If you turn on your Polar BEAT app and then you turn on your OH1, everything should be hunky-dory as you start to record the session.

However, if you go out of range then this will happen

ie when you are out of range NOTHING is recorded.

Even when you return to range NOTHING is retrieved from the cache. You will only ever have what is shown above…ie a gap in your recording.


A: You forgot to specifically turn the caching on.


Even if you had turned the caching on Polar Beat would still have recorded the same track as shown above.

BUT with caching enabled it would have recorded a separate heart rate track. This separately cached track will find its way back to Polar FLOW when it synchronizes. There will then be a (partial) duplicate workout. There is no way to combine these tracks.

Note Well: I imagined Polar have implemented the functionality this way because it is the easiest way to get the technology working and to quickly start selling the product. I would hope & imagine that the way this functionality works will be expanded upon and improved throughout 2018.

To be clear: the retrieval of cached workout data is CURRENTLY only supported within the Polar FLOW APP environment.


There are no kinds of vibrations or audible functionality on the OH1. However, there appears to be only one LED on the device yet it can blink and flash in many and varied colour combinations. These colour combinations are included in the Polar OH1 review but are from In reality, some of the colours are not as obviously different as you would think..but it’s fine:

LED Guide





This LED Flash = No Heart Rate…Obviously…ts red.



Blue flashing LED = Sync’ing


Any Polar OH1+ Review is not complete without a good look at the accuracy of the product.

I have used the OH1 for well over a year and, in my opinion, it is the most consistently accurate optical HR device. It almost always matches results from my chest strap. This awesome performance is partly because I wear it on my upper arm but even then it performs a little better than the Scosche or Wahoo TICKR FIT, each of which are also acceptable performers.

The Polar OH1+ is bravely targeting the indoor gym/fitness crowd as well as the outdoor endurance crowd. Generally speaking, accuracy is hard to achieve in gyms/classes and when cycling and when running hard intervals and when swimming. But with the OH1+, accuracy is generally GOOD in those sports.


I did a 20-minute workout to simulate a weights and gym session. 75% upper body where the arms were moving. But even with the 25% of the time on the lower body, I was holding weights which should affect/restrict blood flow in the arms to some degree.

The blue line is for the WRIST-WORN oHR device, in this case, it was the Suunto Spartan Trainer. The wrist has the greatest number of potential bad movement for optical technology so you could equally substitute any other wrist device here and possibly get the same sort of inaccurate results.

Even the Scosche was struggling a little at times.

In this workout, the OH1 is clearly the closest to the chest strap (Suunto Spartan Sport). Not perfect, but pretty good.

Below is a similar workout on the following day but this time the Garmin 235 is the source of optical HR. Again, the wrist-based device has the most problems. You could then classify the Scosche or the OH1 as being equally as good, or equally as bad as each other – depending on your perspective. The only thing of note here would be several ‘straight lines‘ from the Scosche, presumably where it read nothing and guessed at what was in between the readings it did have.

I would say that the Scosche and the Polar OH1 are just about acceptable in the above scenario.

Personally, I would use a chest strap in a gym. But, to be brutally frank, there isn’t much point in recording heart rates as low as these. I typically combine weights with, say, a Wattbike in the same session. So really I’m wearing the HRM for the bike that comes later.

However, the charts above represent a typical ‘worst-case scenario’. YOU may well be looking at indoor classes rather than weights. My guess would be that for the CLASS scenario you will typically get better results than I got for weights but not as good as those for running. So, I’d say the OH1 should be good enough for recording reasonably accurate HR in gym classes.


I draw the line at wearing a plethora of electronic gadgets whilst swimming for any review let alone this Polar OH1+ review. So here we have to assume that the Suunto SMARTBelt is correct. As you can see the wetsuit held the OH1+ in place and everything is good (enough).

. Not sure why avgHR is zero. Strange (was created as part of a Suunto multisport session)

This time it’s a pool swim. And I have to say this is probably the best ever optical HR I’ve seen in a pool. It’s not perfect. But it’s the first time I’ve been able to acceptably use an arm-worn sensor. There was a wristwatch at the same time but the results were not good and distracted from the message about how good the OH1 is when compared to the Suunto chest strap below. I really tried to dislodge the OH1 but failed, I tried so hard I got cramp. I tried all sorts of paces and rests and, as you can see, it’s pretty cool.

And here we have another short pool swim but this time using the clip for the goggles. Again. Awesome.

OH1+ With Goggle’s Clip


Things look great on this steady state run with all 4 devices performing in a manner that I would consider acceptable for my needs. A good sign is that they all give the exact same average HR but, more importantly, drilling down to the detail shows a great match. The Garmin 235 (optical, wrist) is the worst of the 4. Visually inspecting the lines when the chart is enlarged shows that the Polar OH1 is perhaps even a closer match to the Suunto chest strap than the SCOSCHE

Slightly different run and one of the better I’ve ever had with 4 devices concurrently. This time the Polar M430 (with the same Polar 6-LED sensor) takes the role of the wrist-based HR device, with the Polar OH1 data being cached. Only a very slight dropout of the M430 near the start. This session was under-over aerobic threshold with a fast bit at the end to see how the devices reacted to an immediate stop afterwards. All good.

Finally here are some half-hearted hill reps. Awesome performance against the HRM-TRI.

: they REALLY are different if you look VERY closely


Here is another chart that illustrates that wrist-worn oHR is prone to issues, with the SCOSCHE and Polar OH1 performing well. The Scosche got it notably wrong in a couple of places, the Polar OH1 performed slightly better but didn’t quite make it all the way down to the true troughs that the Suunto SMART Belt recorded – very close though.


And here is a 5 device HR extravaganza. It is no coincidence that the two wrist-worn sensors effectively fail miserably – the Garmin 235 and the Polar M430. Over a 2.5 hour ride, there is no hiding the potentially obvious conclusion that wrist-based optical HR can be inaccurate when cycling (we already knew that).

At about 23 minutes there is a blue spike. This is potentially the only interesting anomaly of the non-wrist devices. Here the chest strap spikes…so we are in a situation where the Scosche and OH1 are probably right and the chest strap wrong. The chest strap may have moved, for example.

Here’s another saying pretty much the same thing. This time it’s the two devices to show how close the OH1 is to a chest strap.

: they REALLY are different if you look VERY closely

This is on a turbo trainer and the results are great, as expected



If you check out any of the more significant reviews of other devices on this site they will normally include a section on HR accuracy and normally also include the OH1 as the ‘reference device’ for the best that oHR can deliver. Very many tens of tests have all shown the oHR to be acceptably accurate for my high standards.

When worn on the upper arm or on the goggles for swimming, the Polar OH1+ can be classed as ‘SUFFICIENTLY ACCURATE’ across all the sports tested.


The Scosche RHYTHM+, RHYTHM24 and Wahoo Tickr FIT are the only directly comparable alternatives that I would even recommend you to consider. Broader alternatives include chest straps and optical wristwatches and optical bands of various flavours.

Scosche – it’s bigger and has a shorter battery life. It can’t cache HR data. It can’t, therefore, work underwater. Accuracy is similar to the OH1+.

DETAILED REVIEW: SCOSCHE RHYTHM+ Optical HR Band Review Dual Bluetooth Smart + ANT+

Staying with Polar you could instead upgrade to their best chest strap which is the H10 (link to: Polar H10 Review)

Polar H10 Review (2019 update) Comparisons, Polar’s Greatest HRM

Or you could use Polar’s newer LED sensor in their latest Vantage M sports watch but you will probably not find the WRIST to be able to produce as accurate data as the OH1+ worn on the upper arm.

Polar Vantage M Review

2018 saw the arrival of a directly competing product from Wahoo Fitness called the TICKR FIT. The accuracy is perfectly acceptable. It has a much superior battery life but it has no caching and so can’t be used underwater.

Wahoo Tickr Fit Review | Best Optical Heart Rate Monitor?



My research for this Polar OH1+ Review found that the OH1+ will pair with most modern sports devices and apps.


Source: Polar (link to:

Product Manual (link to:


I like the OH1+ and would recommend it and I hope this Polar OH1+ review demonstrates that. I’m including these problems for completeness. Most of them are minor.




At the end of this Polar OH1 Review all I can say is that this is a great product that I do not hesitate to recommend

Its strengths lie in the support for the increasing number of sporting APP users and the comfort of the wear-position. It has many and varied uses across lots of sports.

It’s one of the most accurate optical HR devices I’ve used. If not, THE most accurate one.

Polar addresses the needs of its target markets very well.

The only issue that Polar really need to address, and it’s a minor one, is that they somehow need to combine a cached HR track with other data created on one of their Vantage watches to create one entry in FLOW.

Still. None of that is going to stop me using it A LOT.


10% off…see below

Availability now. Initial pricing is $/Eu80 and GBP70. Replacement straps are £17 or Eu/$18. Existing OH1 owners can buy the Swimming clip for about $/£/Eu5.

Use the checkout 10% discount code: the5krunner10 ( or


If you enjoyed this Polar OH1 review then please purchase through PowerMeterCity in the USA or NewRunningGear in the UK. Both sites will give you a 10% discount on most models with the codes: TFK10 (for NewRunningGear) – if it doesn’t work try the5krunner10 (teething probs! sy) and the5krunner10 (for PowerMeterCity).

NewRunningGear with 10% discount code

Reader-Powered Content

This content is not sponsored. It's mostly me behind the labour of love which is this site, meaning it's entirely reader-powered content I'd really appreciate it if you'd follow, subscribe or Buy Me A Coffee Alternatively please buy the reviewed product from my partners (which costs you no extra) and, for that, I receive a small commission. Thank you!
FTC: Affiliate Disclosure: All links pay commission
Exit mobile version