Verdict

Pros

• Light and comfortable
• Accurate readings
• Works with smartphones and third party apps
• Great companion app

Cons

• Slightly difficult to unscrew back to access battery

What is the Polar H7 Heart Rate Sensor?

The current trend may be to move heart-rate monitoring away from the chest and over to the wrist but accuracy at these new locations is still questionable. The Polar H7 heart-rate monitor takes the traditional chest strap and adds Bluetooth Smart support giving you heart rate data on sports watches, compatible gym equipment and phone app.

Priced at £40, it’s a more affordable option than paying for something like the TomTom Runner Cardio watch or the Fitbit Charge HR, as long as you’re happy to still carry your phone around. You’ll still need to wet the electrodes and strap it underneath your gym shirt, but if you can live with that, the H7 is comfortable, reliable and delivers the all-important data without issues.

Polar H7 Heart Rate Sensor – Design and Features

Polar doesn’t spring any big surprises with the way the H7 works or looks. In the box you’ll get the small, lightweight clip-on transmitter and the adjustable material chest strap. The elastic strap comes in XS-S or M-XXL options so it should fit most chest sizes and uses a simple clip and loop mechanism to secure the H7 in place. It doesn’t budge as long as you’ve secured it correctly just below the chest muscles and when it’s underneath a shirt, there’s no discomfort or irritation. This is often one of the biggest complaints associated with chest straps, but you don’t need to worry about that here.

Concealed behind the back of the small transmitter lies the CR2025 coin battery which should lasts for month as long as you disconnect it from the strap when not in use. That’s important because the sweat and moisture from a workout can activate the transmitter and drain the battery. This is the kind of battery you’d find inside of a watch and it only costs a couple of pounds to replace. A coin should be enough to loosen the back to replace, however it’s pretty stiff and we found keeping a screwdriver nearby handy.

The H7 is waterproof so you can wear it for swimming although the Bluetooth connectivity will not work. If you want to receive heart-rate data underwater you’ll need to use on of Polar’s watches, which use GymLink connectivity. Wearing it under a swimsuit is the most advisable option just in case is not perfectly secured but it’s certainly nice to have the option.

Polar uses an ECG (electrocardiogram) heart-rate sensor so unlike the light-based optical sensors used in the TomTom Runner Cardio and the Jabra Pulse earphones for instance, it measures the electrical activity of the heart to deliver continuous and resting heart rate data. While it’s not 100% accurate, it’s still regarded as more reliable than optical sensors, which in contrast, detects changes in blood volume.

The H7 uses Bluetooth Smart so it’s compatible with iPhones running on iOS 7 and above as well as Android smartphones on Android 4.3 or later. It’ll work with apps such as Runkeeper or Strava and Bluetooth Smart sports watches such as the TomTom Runner Cardio. It also supports 5kHz transmission or GymLink as it’s better known which can be found on many of Polar’s sports watches and the Polar Loop activity tracker.

Polar H7 Heart Rate Sensor – App

As mentioned, the H7 has pretty decent app compatibility. Additionally, Polar offers its own Polar Beat app, which is free on Android and iOS. It’s largely focused on running but it can be customised for cycling, skiing, strength training and a whole host of other activities.

You can also pair it with stride sensor plus customise training by distance, duration or simply free training. In the settings, there are options to add voice guidance, save body measurements and decide whether you want to share your exploits on Facebook or Twitter.

There are additional in-app purchases available to add a fitness test and gain access to a running index. At a cost of £2.29 and upwards, they don’t come cheap and you should be able to find similar information in free fitness apps available on the App Store or Google Play.

Most importantly, sessions are broken down into easy-to-digest sections displaying information on routes and analysis of heart rate. This shows the fluctuation of the heart rate during a workout and the time spent in different heart-rate zones.

As a companion app, it’s one of the better ones,especially in comparison to Garmin’s offering. You can spend money to enhance the experience, but we’d say it’s not that vital unless you’re seriously training for an event.

Polar H7 Heart Rate Sensor – Performance

In contrast to the reliability issues we’ve experienced with smartwatches and activity trackers, heart-rate monitoring with the Polar H7 has been faultless

After strapping it around the chest, we synced it with the TomTom Runner sports watch and a selection of iPhone apps including Runkeeper and the Polar Beat application. There’s little-to–no waiting time for the smartphone or the watch detecting the Bluetooth signal and start relaying the data in real-time.

Wearing it during a gym or running session is not as obtrusive or uncomfortable as we’d thought it might be and thanks to the secure fit, does not suffer any signal drop-outs. We compared it to the Adidas MiCoach Fit Smart and the Mio Fuse, both of which are based on the same optical Mio heart rate sensor technology. We also ran it against the Fitbit Charge HR and the Jabra Pulse heart-rate monitoring earphones.

The screenshots below illustrate how well the Polar H7 does against the Mio Fuse sportsband, which uses the same accurate Mio optical heart rate sensor as the Adidas MiCoach Fit Smart:

Polar Beat app with the H7 (left) and Mio Go app with the Mio Fuse (right)

While all three of the wrist-worn devices were generally accurate, all have their moments when the signal drops out. Those issues appear to be affected by how securely the sensor sits against the skin. With a chest strap monitor like the H7, you don’t have those problems.

Should I buy the Polar H7 Heart Rate Sensor?

If you want a reliable heart-rate monitor and can live with strapping onto your chest, the H7 is an excellent option and well worth the money. There’s already extensive app and sports watch support available to combine it with. Crucially, it just works without problem.


Even at £40, it’s not an unreasonable investment if you plan to use it regularly. As along as you remember to unclip the transmitter when you’re done, it should last for quite a while too.

SEE ALSO: Best Fitness Trackers

If you are dead set against wearing a chest strap heart-rate sensor, then the cheapest activity tracker with the technology built in is the Mio Fuse. It’s an activity tracker that delivers accurate heart-rate tracking, but it’s not without its issues elsewhere. The heart-rate-monitoring Jabra Pulse earphones and TomTom Runner Cardio sports watch are good alternatives, but significantly more expensive.

We still say this is the most reliable way to monitor heart-rate activity, but as wrist-based monitors improve, it might not be long before they are a thing of the past.

Buy Now: Polar H7 Heart Rate Sensor at Amazon.co.uk from £41

Verdict

If you’re not convinced by the growing legion of heart-rate monitor-packing watches, the smartphone- and sports watch-friendly Polar H7 is one of the best chest-strap monitors we’ve trained with.

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