Best heart rate monitor: chest straps and HR watches compared

Want to get fit, fast and strong? Just listen to your heart with these wearables
Best heart rate monitors 2021
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Using a heart rate monitor is the best way to get more data from your training sessions, and that's useful whether you're a novice runner, or a serious athlete. Everyone can gain something from monitoring their heart rate.

Chest strap monitors are still the most accurate for working out, but heart rate monitor watches (and smartwatches) are now excellent options – if you use them in the right way. We've outlined that information below.

And heart rate monitors are for more than sport. The latest devices can help monitor your heart rate 24/7, help spot illness, stress, tiredness – and help tell you when to take a break.

We've reviewed and tested pretty much every heart rate monitor on the market – this is our list of picks.

How to buy a heart rate monitor

When people ask us what's the best heart rate monitor to buy, we always ask two questions:

What kind of exercise/how important is accuracy?

This is the most important consideration – how do you workout and how much are you relying on the data?

Running and cycling workouts are usually fine for an optical sensor on the wrist, but high intensity workouts and functional fitness (such as CrossFit) is better suited to an EKG chest strap, or an optical sensor in a more stable position, such as the upper arm. That's because lots of movement creates signal noise that affects accuracy.

It's also key to be honest with yourself about how you'll use the data. If it's to check how hard you worked and as a guide to intensity, the slightly less accurate wrist-based sensor can often be good enough for some people.

But if you're using HR to train in real-time, or you need the best quality data possible to input into your Olympian-level training plan, only the accuracy and responsiveness of a chest strap will cut it.

What kind of device do you already have?

When it comes to chest straps, some use ANT+, which is only compatible with specialist running watches that use that same connectivity – i.e. Garmin, Polar and Suunto watches.

Those who want to use their phone to work out will need to look for a Bluetooth-enabled strap, which will connect to apps like Strava, Runkeeper and Endomondo. These can be paired directly to a smartphone, and to smartwatches as well.

Which type of heart rate monitor is most accurate?

Chest strap v heart rate monitor watch

Optical sensors explained

The biggest battleground is chest straps versus wrist devices. The latter use an LED array to "see" the blood pulsing through your veins, and estimate your heart rate.

Optical sensors are integrated into most wearables from the likes of Garmin, Fitbit, Polar and Apple. They're more comfortable and convenient, and, if you're running steadily, should do the job just fine.

However, when you start ramping up the intensity, doing functional fitness, or HIIT workouts, optical sensors placed on the wrist can't cope with the rapid rises and falls in BPM. They can also be flummoxed by movement of the wrist in exercises.

Dark skin and tattoos can affect accuracy, as skin tone can affect the light reflection. Sadly, not enough work has been done across the board to overcome accuracy issues because of ethnicity, so if you have dark skin and want the very best data from your workouts, think about a chest strap.

Chest straps explained

Chest straps use electrocardiogram (EKG) sensors, which are more accurate and responsive to rises and falls in heart rate, and the relatively steady position on your chest makes the data less noisy.

However, you do sometimes have to wet the sensor to get a good signal.

A third way?

However, there is a compromise. There's been a rise of the heart rate arm band, devices that use optical sensors but placed (usually) on the upper arm. This offers a more stable position, which is less likely to suffer signal interference, while still being comfortable.

Wahoo Tickr X

Price when reviewed: $79.99/£64.99

Wahoo Tickr X

Wahoo's top-end heart rate monitor has been updated, and it's now smaller, lighter and better for tracking without taking your phone or running watch along.

The new Tickr X weighs just 48g including the strap is one of the lightest you’ll find. It uses ANT+ (used by Garmin devices) and Bluetooth connectivity and can broadcast bpm data to three different devices simultaneously.

But runners will love the extra data the new Tickr X provides.

It can track cadence, vertical oscillation and ground contact time in running activities, and the new Running Smoothness score pulls these metrics together to offer a singular assessment of your running style. It's much the same data as you'll get on Garmins with the Running Dynamics pod, and we love the focus on form and technique.

The TickrX can store 50 hours of workouts on board the sensor itself, so you don’t need to take your phone out with you to get the data – and it will appear in the Wahoo app. And it will track 500 hours before you need to change the battery.

It looks the part, will give you that accurate hit of data and is available at a good price too.

Polar H10

Price when reviewed: $89.95/£79.99

Polar H10

As we've already mentioned, if you care about accuracy then for us it's still the chest strap and the Polar H10 is the one we've found to be one of the most reliable.

The iOS and Android-friendly strap boasts Bluetooth and ANT+, so you can pair it to a whole host of devices and third party apps, including Garmin sports watches if you like.

It also introduces a modified design, adding silicon friction dots to help keep the strap in place, plus it's a bit more comfortable to wear.

It still uses an ECG-style sensor that detects the electrical activity of the heart to deliver your BPM readings, but a new measuring algorithm and extra interference-preventing electrodes help improve accuracy.

It's waterproof, so you can go swimming with it although it won't track heart rate intervals in the water. There's onboard memory to store a training session, just in case your phone or wearable dies on you.

We've been using it to test against a lot of the new fitness trackers and smartwatches that have landed at Wareable HQ recently, mainly throwing data into Strava and the Polar Beat app, which is built for heart rate-based training. It's still a chest strap we go back to and can comprehensively say it still delivers the goods.

Sample Polar H10 data

Sample Polar H10 data

Polar H9

Price when reviewed: $59.95/£52.99

Polar H9

The H9 essentially replaces the older H7, coming in cheaper than the H10 too if you don't want to spend almost $100/£100 for a chest strap.

What's the big difference between the H9 and the H10? There are a few things. It misses out on the new Pro strap, which is designed to offer a more comfortable fit. It sticks with the strap used on the now retired H7. In our time with it, comfort was a major issue. If anything, we preferred the slightly more hugging fit.

It also doesn't offer the ability to store workouts or pair to two Bluetooth connections at the same time. If you can live without those features, you're still getting a heart rate monitor that delivers where it matters.

It's the same ECG-style method of tracking your heart to give you the best accuracy. It has ANT+ and Bluetooth connectivity support and works with a host of third party apps. We've also successfully paired it up with Garmin, Polar and Suunto watches too. You're also getting a 30 metre water resistant rating, making it suitable for tracking heart rate for swimming.

Polar's companion Beat app is great if you're very much focused on heart rate-based training, letting you zone in on the metrics and insights that matter. We've used it for plenty of running (both indoor and outdoor) and like the H10, it's accurate and the most reliable way to get data you can trust.

Sample Polar H9 data

Sample Polar H9 data

Garmin HRM-Pro

Price when reviewed: $129.99/£119.95

Best heart rate monitor 2020: watches and chest straps compared

The Garmin HRM-Pro is smarter than your average chest strap that also promises to give you that accurate hit of HR data. So along with measuring your heart rate with an ECG-style sensor, it's also going to serve up a raft of additional metrics to delve into post and during a run.

Those advanced running stats are cadence, vertical oscillation, ground contact time, ground contact time balance, stride length and vertical ratio. If you know what those terms mean (if not, check out our running watch data guide), these can help to identify areas of your technique and running form that could help improve running style and hopefully get you running better and quicker.

Back to heart rate monitoring, and the HRM-Pro connects to devices using ANT+ and has a 5ATM waterproof rating making it safe for the pool and open water swimming. It's powered by the kind of coin cell battery you'll find powering a lot of watches. That should last you up to a year, before you need to pop it out and replace it.

If you participate in team sports, it can also now track additional metrics like steps, intensity minutes and all-day heart rate data.

We've used the HRM-Pro for plenty of testing including putting it to the race test where it was comfortable to wear and crucially delivered the data that mattered. If you've got an ANT+ friendly device and want that extra hit of accurate HR data and advanced running metrics, it's definitely one to check out.

Sample Garmin HRM-Pro data

Best heart rate monitor 2020: watches and chest straps compared

MyZone MZ-3

Price when reviewed: $79.99/£79.99

MyZone MZ-3

If you want more from your chest strap, the MyZone MZ-3 goes beyond churning out simple bpm (beats per minute) recordings. You earn points based on your bpm. It's also integrated into a whole host of fitness classes at studios and gyms globally.

Rather than simply scoring highly based on a high reading, the MyZone studies your effort over time and creates a golf-style handicap for your level. Your aim is to better your own performance, and like golf, MyZone adds a gamification element enabling you to compete against others, even at vastly different abilities.

Design-wise, it's your pretty conventional chest strap with a red elasticated strap, which comes in three sizes, along with the module you can clip out. It also has an internal memory - capable of storing 16 hours of data - so you don't always have to exercise while carrying your smartphone, which is useful for gym classes.

It offers a 7-month battery life from a single charge and is waterproof down to 10 metres so you can take it for a swim too.

If you do keep your smartphone nearby, you'll also benefit from the live stats along with the league tables, personal goals and challenges to keep you motivated.

In MyZone-supporting gyms this data often appears on big screen during your classes. The app has improved over the years too, adding new features that puts that heart rate monitor to better use.

Sample MyZone MZ-3 data:

Sample MyZone data

Garmin HRM-Tri

Price when reviewed: $129.99/£119.99

Best heart rate monitor 2020: watches and chest straps compared

There are a lot of wrist-based sports watches that claim to offer accurate heart rate monitoring in the water. We are talking about the likes of the Polar Vantage V2 and Garmin's latest Forerunner watches. The Scosche Rhythm24 armband, Polar OH1+ (which can be worn on your goggles) and new Polar Verity Sense promises accuracy on par with a chest strap too. We haven't tested those comprehensively enough to say they do deliver the goods, so for now we are going to stick with a chest strap that does.

The HRM Tri strap from Garmin is a real pro tool for triathletes. It's an ultra-small and light (a mere 49g) heart rate strap that adds considerable bike and running smarts to some of the pool functions of the HRM Swim.

With a built-in accelerometer that'll deliver cadence, vertical oscillation and ground contact time data (like Garmin's HRM Run) while on two legs, plus HR stat storage while actually underwater, this is one of the most rounded tools for the three disciplines out there. Garmin has also ensured there are no exposed seams and all edges are soft and rounded, to prevent rubbing or any wetsuit-doffing difficulties.

Polar Verity Sense

Price when : $89.95/£79.99

Heart rate monitors update draft

The Verity Sense sees Polar take the design of its OH1 and OH1+ heart rate monitor armbands and improve to make it a better fit for more workouts.

It uses the same optical sensor technology used in the OH1 devices and offers many of the same features. It now introduces a higher quality strap that can be worn on your upper arm of bicep to deliver heart rate data accuracy comparable with a chest strap monitor.

That strap is machine washable and the cradle that holds it in place solves one issue with the OH1 by preventing it from flipping over. That cradle also doubles as a Bluetooth antenna to increase connectivity range to 150 metres.

There's both Bluetooth and ANT+ connectivity letting you pair it up to a range of apps and other connected equipment, Battery life has been boosted to 20 hours and now has internal memory for 600 hours worth of workouts. Those workouts can now be synced over to Polar Flow, which was previously unsupported.

While the sensor technology remains the same, it's now easier to choose between transmitting data to device, recording a workout on the device or taking it into swim tracking mode. You're also getting a new swim adaptor to make sure it stays securely in place when you're in the water.

Accuracy against a chest strap monitor was very solid in our testing. For runs, indoor rowing sessions and home workouts, it rarely threw out any wild data like many watches have a habit of doing. We'd still opt for a chest strap for supreme accuracy, but the Verity Sense gets very close and should be good enough for most.

It's $10 more expensive than the OH1, which is still available. With bigger battery life, larger internal memory an improved strap design and the same reliable sensor tech, there's some good reasons to make the upgrade and pick it up before other armbands.

Sample Polar Verity Sense data:

Heart rate monitors update draft

MyZone MZ-Switch

Price when reviewed: $159.95/£139.50

MyZone MZ-Switch

MyZone's Switch gives you an armband monitor, wristband monitor and the traditional chest strap kind to offer more versatility in terms of how you get that hit of heart rate data.

It has both ECG and optical heart rate sensor technology onboard, with the idea that you use the two different methods on different parts of the bodies for activities where they are best suited to give you the best results.

So, for HIIT workouts, stick on the chest strap, for indoor cycling you can wear it on your wrist and use the optical sensor while wearing it on your upper arm will give you good data for runs.

The Switch has both ANT+ and Bluetooth connectivity to connect to a range of devices and apps and does of course work with MyZone's own companion app. There's 36 hours of storage and it's waterproof up to 10 metres, which means you can take it for a swim if you want HR data in the water.

Battery life is anywhere from 3-6 months, with regular use of the optical sensor offering a bigger drain than the ECG sensor. Crucially, if you stick to the recommended wearing positions for different exercises the Switch can give you good data you can rely on. If you like the option of having multiple places to track your heart, this is the one to do it with.

Sample MyZone Switch data:

Best heart rate monitor: chest straps and HR watches compared

Wahoo Tickr Fit

Price when reviewed:$79.99/$64.99

Wahoo Tickr Fit

Worn on the forearm rather than the chest, many will find the placement of the Tickr Fit more comfortable and favourable than a standard strap just like the Polar Verity Sense.

Unlike the Tickr X, the Fit uses optical heart rate sensors rather than standard electrocardiography. This has been much maligned for accuracy at peak and high intensity, but thanks to the upper arm placement, we found accuracy to be almost indistinguishable from a chest strap.

It'll dish out calorie burn data and is equipped with Bluetooth and ANT+ support so you can pair it with a whole host of fitness apps, smartphones, GPS bike computers and sports watches.

It's a great alternative to a chest strap, has 10 more hours of battery life than Polar's Verity Sense and crucially for an optical sensor, we found it matches up to chest straps in our side-by-side tests. If you hate wearing something on your chest, the Tickr Fit is a great option to consider.

Sample Wahoo Tickr Fit data:

Best heart rate monitor 2020: HR watches and chest straps compared

Scosche Rhythm24 HR

Price when reviewed: $99.99/£89.99

Scosche Rhythm24 HR

While the Scosche Rhythm+ 2.0 has recently been unveiled, the Rhythm 24 is the more feature-packed option from the company that first sought to deliver heart rate monitoring from higher up the arm before Polar and Wahoo.

Like its predecessor, the Rhythm24 HR sits on the forearm to track your BPMs. The idea is that there are less motion artefacts that can impact on a reading that can happen further down on the wrist.

It's available in a range of different coloured bands, is waterproof and has the ability to store workouts onto the wearable and then sync it later. The LED lights built-in indicate your current heart rate zone while training and can also indicate when you need to stick it back on the charger.

The Rhythm24 is ANT+ and Bluetooth Smart compatible so you can use it with a whole bunch of third-party fitness apps, sports watches and sports equipment. There's also the Scosche companion app where you'll find dedicated profiles for a range of activities. It's clean, simple and very easy to use keeping you firmly focused on that heart rate data. At 24 hours, it has the longest battery life of the heart rate monitor armbands available now.

We've tried the Rhythm24 HR and the sweat-proof and water resistant wearable passed the high intensity interval test. Plus, it was also very comfortable to wear during our workouts. It's also capable of measuring heart rate in the water as a bonus.

Bottom line, Scosche proves you can comfortably wear a heart rate monitor elsewhere on your body and still get those results you crave.

Check out our Scosche Rhythm24 HR review to find out more about the heart rate monitoring armband.

Sample Scosche data:

Sample Scosche data

Whoop Strap 4.0

Price when reviewed: Free with $24/£24 a month subscription

Best heart rate monitor: chest straps and HR watches compared

The Whoop Strap 4.0 is a unique beast – acting as a 24/7 heart rate monitor – designed to help you determine the effect of workouts on your body after you've left the gym.

The band itself doesn't have a screen, and the fabric strap dominates the design. It's muted, unobtrusive and you can wear a watch (or smartwatch) on the other wrist without looking like a dork.

Whoop doesn't track steps and doesn't care about calorie burn. It's not even that good at tracking workouts themselves – and won't give you any realtime feedback on your heart rate.

Instead, it's lazer-focused on the effects of workouts on your body, how much you recover and the quality of your rest – and how ready you are to do it all over again.

It does this by assessing your sleep quality, and the strain of your workouts and day-to-day life. It measures your heart rate variability, and other key wellness factors, to tell you how recovered you are. It will also factor in data on sleep conditions, such as whether you had any caffeinated or alcoholic drinks, worked on a screened device or shared your bed.

It's a different aspect to heart rate monitoring – and one that's more of interest to those doing things like functional fitness and gym training, rather than runners, swimmers or cyclists. Those people could benefit from those insights, but would have to use another tracking device in tandem, and ecosystems like Garmin already do a lot of the recovery stuff in one place.

But it costs a lot. There's a $24/£24 per month subscription – contracted for a year – but you get the Whoop Strap for free.

You can pay less, with an $18/£18 per month subscription, if you sign up for 18 months – but you need to front up (an insane) £324. That's for a wearable with no screen – essentially a heart rate monitor in a black case.

Sample Whoop Strap 4.0 data:

Sample Whoop Strap 3.0 data

Garmin Forerunner 945

Price when reviewed: $599.99/£519.99

Garmin Forerunner 945

The Forerunner 945 sits at the top table of Garmin's sport watch line up, and is designed with hardcore triathletes in mind. It makes use of Garmin's latest Elevate optical HR tech - so it's reliable for runs although problematic for HIIT. You can still pair with a chest strap for better data.

You can train in heart rate zones, receive heart rate alerts, and broadcast heart rate data over ANT+ with paired devices. You can go swimming with it of course, but you'll need to pair it with on of Garmin's HRM chest strap monitors to get reliable data in the water.

And it will produce a tonne of useful metrics from you heart rate data. Training Effect, Training Load, recovery and VO2 Max are all gleaned from tracked runs, using Firstbeat's heart rate variability algorithms. It's actionable and interesting data that can help you learn more about your session.

Outside of workouts, you can also perform HRV stress tests to asses how well recovered your body is for taking on your next workout session. Additional heart rate-based metrics including lactate threshold can be unlocked when it's paired with Garmin's Running Dynamics Pod.

In our testing putting it up against Polar's H10 chest strap, it actually fared really well and is definitely an improvement on what we've seen from Garmin's heart rate setup in the past.

Check out our full Garmin Forerunner 945 review.

Sample Garmin Forerunner 945 data:

Sample Forerunner 945 data

HR sample data: Garmin (left) and chest strap (right)

Garmin Forerunner 55

Price when reviewed: $199.99/£149.99

Best heart rate monitor: chest straps and HR watches compared

Garmin's entry level running watch doesn't scrimp on heart rate smarts – it has a built-in optical heart rate monitor using the company's Elevate technology – the same you'll find on the brand new Garmin Fenix 6.

While it doesn't produce the same amount of analysis from HR data as Garmin's top devices, it will still give you a VO2 Max reading after an outdoor run, and this is tracked in the Garmin Connect app.

And there are some extra features that are gleaned from heart rate data, which make it a powerful training companion, even at a budget price.

The recovery advisor will help runners know when to take a break to prevent overtraining an injury, and there's also a race predictor, which uses VO2 Max to offer guidance on how quickly you can run common distances.

And the Forerunner 55 also hooks up to Garmin Coach to suggest workouts that you can follow.

It still suffers the same dropouts and inaccuracies as most optical sensors at high load - so it's best for steady runners. Of course, you can connect Bluetooth and ANT+ friendly chest strap monitors if you need more accurate data.

But at this price, it's a solid performer in the Garmin range – and if you're looking for a heart rate tracking sports watch that doesn't cost the Earth, the Forerunner 55 ticks a lot of boxes.

Forerunner 55 heart rate data:

Forerunner 55 heart rate data:

Forerunner 55 (left) and chest strap (right) showing very close results from a steady run

Coros Pace 2

Price when reviewed: $199.99/£179.99

Heart rate monitors update draft

Like the Garmin Forerunner, the Coros Pace 2 from emerging sports watch maker Coros is an affordable option that comes packed with features including a heart rate monitor.

It's optical based setup, with support to pair up external heart rate monitors as well. That onboard sensor delivers all the things you'd expect including continuous monitoring, training in heart rate zones, but also feeds that data into Training Load insights and will serve up VO2 Max scores as well.

Our early experiences with Coros watches and its heart rate monitors weren't great, but things have certainly improved since then. For steady paced runs and workouts, the Pace 2 holds up well for accuracy. Pairing up a chest strap monitor is definitely the way to go if you do a lot of interval and high intensity training, but in general it performed well in our testing.

Coros is always looking at ways to put that heart rate data to better use, so it's one that could evolve to become more useful. If you don't want to spend big on a multisports watch and want a good performing heart rate monitor, this is definitely one to look at.

Sample Coros Pace 2 data

Heart rate monitors update draft

Polar Vantage V2

Price when reviewed: $499.99/£449.99

Heart rate monitors update draft

The Vantage V2 is the follow-up to Polar's top end multisports watch where it debuted its new heart rate sensor technology to improve accuracy from the wrist.

With the V2, you're still getting its Precision Prime sensor technology, which is LED based using two different color LEDs and a skin contact sensor to make sure it's taking reliable and accurate readings when you get moving.

That sensor fuels a vast array of features outside of the sports watch staples. It powers Polar's rich training and analysis features and also its advanced sleep monitoring, which is up there with Fitbit for accuracy and insights.

Put to the test, the Vantage V2's HR monitor does a solid job overall. It's certainly not free from the odd wild spike or strangely low heart rate and the start of workouts. In general, it does provide reliable data.

You do have that option to pair up an external heart rate monitor, and if you want to make the most of the V2's best features, that's likely the way to go. Though without it, it should serve many just fine as it did in most of our tests.

Sample Polar Vantage V2 data

Heart rate monitors update draft

Apple Watch Series 7

Price when reviewed: From $399/379 (40mm)

Apple Watch Series 7

We can debate whether you should call the Apple Watch Series 7 a sports watch or a smartwatch, but there's no doubting it's become a solid device for heart rate monitoring.

From a fitness point of view, we've put it through the same rigorous testing as we do with all of the wearables on this list and it really impresses where a lot of wrist-based monitors falter. We're talking high intensity interval training.

Data is viewable inside of Apple's own Workout app but the benefit of having a strong collection of third party Watch apps means you can also view that data in places like Strava and Runkeeper.

If you don't care about working in heart rate zones though, it's well equipped for taking reliable resting heart rate readings throughout the day and with the addition of an ECG, it's now fit to tap into heart rate readings to detect serious heart issues including atrial fibrillation.

That data can be viewed inside of Apple's own Health app and also be exported to a PDF to be shared with medical professionals.

Along with the improved hardware, Apple has clearly done some software tinkering too to improve the performance of its heart rate monitor in a big way.

While Fitbit and Samsung do offer decent heart rate monitoring solutions on their smartwatches, it's Apple's that we think does the best job of making it all work and it actually does a better job than a lot of sports watches too.

Sample Apple Watch Series 7 data:

Best heart rate monitor 2020: watches and chest straps compared

HR compared: Apple Watch Series 6 (left) and Wahoo Tickr chest strap monitor (right)

Fitbit Charge 5

Price when reviewed: $179.95/£149.99

Best heart rate monitor: chest straps and HR watches compared

When it comes to heart rate tracking, Fitbit has really been pushing things forward in 2021. We've picked out the Charge 5 here, because it's the newest device – and it's cheaper than the Versa 3 and Sense. But there's a lot to like, whichever Fitbit you choose.

As a heart rate monitor, it's multifaceted. Fitbit has lurched towards wellness, so the heart rate monitor populates the new Health Metrics dashboard, to keep tabs on key metrics like resting HR, heart rate variability and breathing rate. All of these can be signs of illness if there are spikes and dips – and the data is well-presented.

But workouts are also tracked, and Fitbit has plenty of workout profiles.

Heart rate tracking is pretty accurate (as you can see from the chest strap comparison below), unless you really start testing the sensor with rapid HIIT and lots of arm bending and motion. It's not chest strap accurate – and there's no provision for pairing one if you need an accuracy boost.

However, there are some metrics for people that workout.

The new Daily Readiness Score (for Premium subscribers) is a Whoop-esque assessment of how rested and recovered you are from workouts, using heart rate variability and sleep data.

There's also the Cardio Fitness score, which is a rebadged VO2 Max measurement.

And Fitbit has put new focus onto stress management detection, again leveraging the heart rate sensor.

While the Fitbit Charge 5 isn't a bulletproof heart rate monitor for athletes, it's also no slouch – and offers more insights than a simple chest strap. If you're interest goes beyond what happens in your gym session, it's a savvy purchase.

Fitbit Charge 5 data:

Fitbit Charge 5 data

HR sample data: Charge 5 (left) vs. chest strap (right)