Myzone MZ-3 review – Heart rate monitor that measures effort, not just heart rate

MyZone MZ-3 is quite elderly in gadget years. It even has an upgraded new sibling in the form of the MyZone MZ-Switch. However, its low price, ease of use, reliability, and all-around quality mean it's still among the very best heart rate monitors you can buy.

A recent study conducted by the American College of Cardiology actually tested a bunch of smartwatches and chest straps to find out which would be more effective and found that chest straps prove the most accurate of the heart rate-measuring devices, scoring an average of 99.6% accuracy. The wrist-worn devices in the test, however, proved to be far less reliable. While some devices recorded an accuracy of 92%, there were others that scored as low as 67%.

So there you have it: chest straps provide a more accurate picture of how hard you are going at it during a workout. And now you know why they’re a worthy investment; that brings us to our review of the Myzone MZ-3, a device that has been doing the rounds for quite some time now but is still worthy of consideration, especially if you’re a fitness buff demanding accurate data from your workouts.

It’s also good to know that it will pair with just about any piece of third-party equipment, from smartphones, tablets and smartwatches right through to Garmin receivers and even treadmills and exercise bikes, such as Peloton machines.

Myzone MZ-3 review:  Price and availability

The Myzone MZ-3 activity belt was first launched way back in 2015, originally priced at £129.99 / $180. However, since that time, the chest strap has come down considerably in price and can now be bought from the brand’s official website with a £50.00 discount, costing £79.99 / $110. That gets you the clip-on monitor and the chest strap, which comes in one colour: bright royal red.

Myzone MZ-3 review: Design

While the MZ-3 is rather striking with its vivid red band, the heart rate-monitoring module that clips onto it does look a little on the cheap side, probably because it’s made entirely out of plastic. Still, it’s super comfortable to wear thanks to the stretchy, smooth strap that’s made from Elastan. To be honest, you’ll barely notice you’ve got it on - even for prolonged workouts. It has an adjustable fixture on the band, too, so you can alter it until you get just the right fit.

Another clever design detail is that the Bluetooth module remains switched off until it senses skin contact, which helps to preserve battery life. So if you’re trying to connect it to an external device and can’t figure out why it’s not in the list of available devices, it’s probably because you haven’t put it on yet. Once it is strapped into place, it will give you a beep telling you it's ready and raring to go.

Myzone MZ-3 review: Features and app

Like most heart rate-monitoring chest straps, the Myzone MZ-3 doesn’t have a display. Instead, this function is delegated to the screen of your smartphone. The live workout data you’d normally see on your smartwatches, such as calories burned and heart rate zones, is displayed on a ‘tile’ in the Myzone app. 

While there is a lot to take in upon first use, the Myzone app does a great job of clearly visualising different heart rate zones, so it's easy to see which zone you're in, even if you just glance over to the phone quickly. And if you don’t really want to have your smartphone with you during a workout, the good thing here is that the MZ-3 will automatically sync with your device once it's back in range. 

What differentiates Myzone from other workout platforms is that it will eventually calibrate itself to your heart rate once you've been using the MZ-3 for a while, allowing it to work out what percentage of effort you're putting into each exercise. Effort is the main currency here - rewarding in the form of MyZone Effort Points (MEPS) - and is so much more effective than just measuring calories burned, for instance. It also means an Olympic athlete could effectively compete against someone that hardly exercises, and it will compare their effort percentages to that of a fitness newbie using the same device. 

We think this is a brilliant way of measuring how well you're progressing on your fitness journey and is much more motivating for beginners. There’s a community of Myzone users to interact with on the app, too - which is a great feature for those who like to compete and compare.

Whatsmore, Myzone has been adopted by tonnes of UK gyms, which use the MEPS scoring system technology in their classes so members can compete with one another in real-time. So, once gyms are back up and running - that’s another option you have.

Myzone MZ-3 review: Workout performance

Myzone is no stranger to the world of heart rate monitoring The company has been developing this tech for donkeys, and you can tell. It works effortlessly and we came across no performance issues during our time with it.

One of the best things about this device is its incredible six month (YES, SIX MONTHS) quoted battery life. Obviously, this is just a quote and we didn’t quite have the time to test this out for this review, but after seeing hardly any change in our 100% battery indicator icon post-workout, we were convinced this device will not need charging often. Naturally, the more you use it, the faster the battery will deplete, but even working out everyday you’re unlikely to need to charge this thing more than once a month.

We love how convenient this makes the MZ-3, especially over wrist-worn trackers, most of which need to be charged on a weekly basis. It’s easy to charge, too. Just clip it into its proprietary USB charger and boom, you’re done.

Myzone MZ-3 review: Verdict

The Myzone MZ-3 has an outstanding number of features, especially for such a compact and easy-to-use device. We especially love the emphasis it has on your personal effort as opposed to a more standard calorie burn, which isn’t always the best way to measure exercise effectiveness. This – alongside the app’s community of users – works a treat in helping anyone, of any fitness level, to stay motivated. A huge plus for fitness junkies like us.

The MZ-3 isn't something you’re going to be wearing all day every day like you would a smartwatch. It is definitely aimed more at those who want to collect super accurate data when it matters the most. As a result, it’s not for everyone, but it is a great bit of kit for the serious workout buff, despite its less-than-premium-looking design.

Myzone MZ-3 review: Also consider

The Garmin HRM-Pro combines the best features found in other Garmin heart rate monitors, such as the Garmin HRM-Run and Garmin HRM-Swim, making the HRM-Pro the ultimate choice for – well – pros. Track advanced running and swimming metrics when linked to a compatible smartwatch. The HRM-Pro is more expensive than the MZ-3, but it's also five years younger.

The Polar Verity Sense is a fantastically versatile, feature-rich and well-priced heart rate monitoring strap – but you do have to contend with a not-so-user-friendly companion app. The battery might not last as long as on ECG heart rate straps, but you are repaid inconvenience as it can be worn on the arm and wrapped around your head too. No joke.