Review: Polar OH1+, for accurate heart rate tracking on land and in water
Polar OH1+
Pros
- Accurate HR data in and out of water
- Small and lightweight
- Memory for caching data
- ANT+ and BLE connectivity
- 12 hours of battery life
Cons
- Physical button is tiny
- LED status meanings can be confusing
Polar has announced recently the OH1+. The strap features BLE/ANT+ connectivity and attaches to swim goggles to measure heart rate from the temple.
Essential reading: Best heart rate training monitors
In our review we found its predecessor, the OH1, to be a great product. It makes heart rate tracking simpler than ever. The little gadget is light, comfortable and can be worn around the upper or lower arm. What impressed most, though, is the accuracy of readings. It’s close to what you would get with a heart rate chest strap and much better than a wrist based heart rate device.
I’ve been testing the new version during the past few weeks. Read on to find out what I made of it.
| Design Setup and use The data Overview |
Design
The OH1+ looks exactly the same as its predecessor. About the size of a coin, the small circular optical heart rate unit roughly measures just under 30mm in diameter and weighs a featherlight 5 grams. The strap is actually heavier than the unit coming in at 12 grams.
The sensor slips neatly into the plastic holder that is attached to the velcro band. As before, you can strap the gizmo to your upper or lower arm. This is a one size fits all affair but the armband stretches to a 24-inch circumference which should fit everyone. The strap is changeable and comes in a number of colors.
The OH1+ retains the 3 ATM water resistance of its predecessor and is machine-washable. But now there is another unique way to wear it thanks to a google clip which can be used to secure the unit to swim googles.
This allows for heart rate measurement from the temple. A clever move on Polar’s part as this location is much more conducive to capturing accurate information as it’s not affected by your arms flailing about in the water. The thin layer of fat and muscle at the side of and behind the eye allows for the pulse to be easily measured.
Out of the box, Polar OH1+ works with most sports watches, trackers, cycling computers, gym and studio equipment such as treadmills. It transmits your heart rate via Bluetooth and now ANT+. This last bit is an upgrade many have been patiently waiting for.
Those that prefer training without a watch or a phone will be happy to know the OH1+ has 4 GB of internal memory. This is enough for storing up to 200 hours of training data.
At this point it’s worth noting that the internals of OH1 and OH1+ are exactly the same. The OH1 currently does not transmit over ANT+ but a firmware update (set to land any day now), will bring this functionality to the device. After that, pretty much the only difference between the two will be the swim goggle clip.
Battery life is an excellent 12 hours which is more than enough for even the longest of training sessions. Best of all, the 45 mAh lithium polymer battery is rechargeable which means you never have to go around shopping for replacement coin cells.
The sensor unit slots neatly into a proprietary charger that very much resembles a small USB stick. Plug it in a a computer port or USB power adapter, and the OH1+ will recharge fully in a couple of hours. Interestingly, the charger not only looks like a USB stick, it also functions as one. Install the Polar’s Flow Sync desktop app and you’ll be able to sync and perform firmware updates while charging.
Setup and use
To start using simply pair the OH1+ to an app or device, and you’re set to go. No special installation is needed although when you pair to the Polar Beat app you may be asked to do a firmware update.
The device can be used in a number of ways. In broadcast mode heart rate data is sent via Bluetooth or ANT+ to compatible devices in real-time. In standalone mode heart rate training data is stored internally for syncing later on. This last one is deal for swimming.
The ANT+ is an important add-on. It means that in addition to the single Bluetooth connection, you can now stream your heart rate to an unlimited number of devices via ANT+ in real-time. Ultimately, I’ve not had any issues connecting the sensor to any of my gear. It pairs quickly and once connected it stays connected until you tell it otherwise.
The OH1+ works with Polar Beat, Polar Flow and a wide variety third-party fitness apps such as Strava, Endomondo, MapMyRun, etc. Polar Beat is a great option if you want to record workouts and don’t have a sports watch. The Polar Flow app automatically keeps in sync with the Beat app and provides more detailed stats.
When wearing it is important to make sure the LED optical green sensors on the underside of the main unit are in firm contact with your skin. To ensure accuracy from the outset, it is advisable to wear your OH1+ for a few minutes prior to starting a training session. As with most optical systems, there may be a bit of trial and error on the part of the user as to finding the location to get the best results.
I used the OH1+ in all three locations (upper arm, lower arm, swim goggles) with no problems whatsoever. The only issue I experienced is that because the band is so thin and sensor unit is small, it feels like they are in danger of flipping over. Not a problem when the HR monitor is sitting on your arm, but swimmers may want to consider wearing the thing under a swim cap to keep it firmly in place. You especially need to be careful when rinsing swim goggles between pool lengths. It might flip over and you won’t even notice!
To start your session switch the sensor on by pressing the single physical button on the side of the device. An LED light at the opposite end will confirm this by flashing green several times. The LED light has many other functions. A white light flashing every two seconds indicates that no heart rate is detected, green signifies that it’s on and recording.
To enter standalone training mode, press the button twice. This will be confirmed by 2 quick flashes and a change in the pattern at which the light flashes from that point on. To switch off, just press and hold the button. Red flashing indicates that it’s time to charge the battery and blue that its syncing. There are other flashing patterns with separate meanings which I won’t go into here.
If all this sounds a bit confusing, that’s because it is. While the physical button functions well, it is very tiny which makes it difficult to press. I would have preferred a larger button. Also, it takes time to memorize what each of the flashing patterns means. I can’t help but feel that this could have been made a bit easier.
Nevertheless the OH1+ functions well and is very reliable. At the end of your session all the data is wirelessly uploaded to the Polar Flow/Beat app on your smartphone for convenient review. No need to press any buttons. Simply open up the app and switch on the sensor and your data will port itself over to your smartphone.
All sessions that are recorded in memory are marked by the app as “Other”. A simple tap on the smartphone screen allows you to amend this for the session by choosing from a long list of exercises.
Polar Flow is the place to go to for more detailed stats.
There’s also a Polar Flow web service which you can use to plan your training, track your achievements, export data, get guidance and see detailed analysis of your training results.
The data
Polar tracks your heart rate with 6-LED optical green sensors on the underside of the main unit. The lights bombard your skin using a high rate and a photodiode detects the intensity of the green light that is reflected back. Between heart beats the blood flow is weaker and this results in less light being reflected back. The OH1+ calculates these variations to detect your heart rate.
What you’ll find is that the OH1 is wonderfully accurate, much better than a wrist based heart rate monitor and right up there with what you would get if you were to wear a chest strap. In my test sessions, I found that if there was a discrepancy, it was only by 1 beat or two. And only with very high intensity activities or at the beginning of a session.
Here is, for example, how it stacks up against the Scosche RHYTHM+. Many consider Scosche RHYTHM+ to be one of the most accurate upper arm HR monitors, even better than its more recent sibling the RHYTHM 24. The snapshot is of a recent 5K run. As you can see the average heart rate is exactly the same, the only difference being the OH1+ (dark blue line) shows a maximum heart rate of 168 and RHYTHM+ 167.
At this point you might be wondering, what about a chest strap. Well, here’s another run where I compare it to the Polar H10 chest strap. Very similar, again. The OH1+ (dark blue line) showed an average of 154bmp over 5K and maximum 170bpm. The Polar H10 an average of 155bpm and maximum of 168bmp.
The OH1+’s biggest competitors are Scosche RHYTHM 24 (and RHYTHM+) and Wahoo TICKR FIT. All of these work from the upper/middle arm and come with Bluetooth and ANT+ connectivity. However, Wahoo’s device lacks offline caching while Scosche’s devices comes with a bare-bones app. Also the OH1+ has better water resistance and is the only/best all round solution for swim tracking.
Most importantly, in terms of accuracy the Polar OH1+ is just as good if not better than the others. It only pales in comparison when it comes to battery life – 12hrs versus the 24 hours on Scosche Rhythm 24 and 30 hours on TICKR FIT. Not that 12 hours of battery life is anything to whinge about. It allows for more than a few training sessions.
Overview
The verdict
The new and improved version of the Polar OH1 comes with a few upgrades which work very well. A feature many have been waiting for ANT+ connectivity has been slapped on, along with a clever way of monitoring your heart rate from the temple when swimming. Given its predecessor’s excellent reviews, it’s no surprise that accuracy is great both on land and in the water.
Of course, not everything is perfect. It never is. The physical button on OH1+ is perhaps a bit too small for my liking and getting used to what each of the LED flashing patterns/colors means takes some time.
 | Polar OH1+ |  |
Nonetheless, this is currently one of the best middle of the road solutions if you’re planning to ditch the old chest strap. It’s light, comfortable, has memory for caching, a great software ecosystem and is easy to sync. There’s actually very little not to like. Polar now has a very competitive standalone optical heart rate sensor in its product range.
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