But not everyone finds chest straps comfortable, which is why the Polar OH1 exists.
So how is the Polar OH1 – also an optical monitor – different? First, it has the benefit being worn on the inside of your (upper or lower) arm, where there’s typically less hair than the outside of the wrist and it’s easier to get a strong, accurate reading. Its elastic strap also ensures it’s snug at all times, which isn’t always so easy to achieve with a silicone watch strap.
Compared to a chest monitor, it’s much easier to put on and take off and it’s less irritating during exercise. So how well does it compare with a chest strap in terms of accuracy and reliability? Read on to find out.
One feature that gives the Polar OH1 a distinct advantage over many chest-based monitors is that you can use it on its own, without taking anything else with you when you exercise. Simply double press the button on the side of the sensor after turning it on and it starts logging heart-rate data to its internal storage. To finish a workout, all you need to do is switch the sensor off.
The OH1 can store up to 200 hours of training data and, once you’re finished exercising, you can sync this info to the Polar Flow app, either via Bluetooth or by connecting it to your PC. The monitor’s Bluetooth connectivity means it can also broadcast data to a wide range of devices including smartphones, gym equipment and fitness trackers (such as Polar’s own watches and bike computers).
That’s a great if you normally use an app such as Strava to log runs and bike rides on your phone, and you simply want to get more insights into your workouts by logging heart-rate data. It’s worth doing some research to check if the OH1 will work with your particular device, though, because I failed to pair it with a TomTom Spark, even though the same watch connects with a MyZone chest-strap via Bluetooth.
Unfortunately, there’s no ANT+ support either, so the monitor will only work with the latest Garmin watches and bike computers that have both ANT+ and Bluetooth smart sensor support.
One area that the Polar device stumbles compared to a traditional chest strap is battery life. Where you might get the best part of a year from a single battery in a chest monitor, Polar says the OH1 lasts only 12 hours between charges. Having said that, this should be enough for all but the longest of endurance workouts and if you need to top the battery up doing so is as quick and easy as popping the sensor out of its strap and into its accompanying USB dock.
In terms of comfort, I was impressed by the Polar OH1 when using it on my left forearm during a bike ride. The elastic strap is easy to adjust and, once in place, I never found it slipped or needed readjusting. Unlike a chest strap, there’s no need to damp the contact points to get a signal, either, and it can be removed within seconds, without having to remove any upper layers of clothing or exposing your wobbly torso.
The OH1 is waterproof, too, so you can leave it on in the shower or pool. In fact, Polar claims the device is “suitable” for swimming; I’ll be investigating this further to see how well the optical sensor works in water over the coming weeks.
On land, though, I can confirm it performs exceptionally well. Cycling can wreak havoc with even the best wrist-borne optical sensors because of the vibrations that are transferred through the handlebars to your wrists, but the OH1 didn’t skip a beat on my bike ride. As you can see from the diagram below, it produced results so similar to my Garmin chest strap that the two red lines are almost indistinguishable. The third line, which bearsbares very little resemblance to the others, is the heart-rate data logged by my Garmin Vivoactive HR multisport watch.
Although the Polar sensor sometimes took fractionally longer to respond to spikes in my pulse during short, steep climbs, it recorded an identical maximum heart rate to the Garmin chest strap and the time logged in different heart-rate zones was also within 2% for every zone. In fact, these figures might have been closer still, had my chest strap not produced gappy data at different stages of the ride, perhaps as a result of interference.
In summary, the Polar OH1 might not be a true replacement for a chest strap heart-rate monitor – in truth, you just can’t compare the two – but it’s likely as close as you’ll get.
The data recorded by the optical sensor was near identical to that captured by a Garmin chest strap, to the point that I had to double check I wasn’t looking at the very same file at first.
Moreover, the Polar OH1 is small, discreet and comfortable, making it the perfect training companion for anyone who wants to record reliable heart-rate data without the hassle of wearing a traditional chest strap monitor.