The best heart rate monitors will provide more accurate readings than smartwatches, no matter how advanced optical heart rate sensors are. Due to their placement, wrist wearables can only ever get so accurate, so if you need accurate data for training, you should get a proper heart rate monitor.
Heart rate monitors, especially the chest strap variety, provide more accurate heart rate readings for two reasons: firstly, they don't need to 'see' your skin like optical sensors, and secondly, the sensor is mounted on an elastic strap that fits the torso better.
In some cases, wearing a heart rate monitor is the only option to track heart rate during workouts: weight training, especially when kettlebells are involved, can't be tracked safely and precisely using wrist wearables. Even the best running watch won't be able to withstand the repeated impact of a kettlebell when doing snatches.
Some wearables, such as the best triathlon watches, can measure heart rate underwater but just like during running, you'll get more accurate results wearing a water-resistant heart rate monitor. If you plan to upgrade your running gear, also check out T3's best running shoes and best running headphones guides.
Best heart rate monitors to buy right now
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. With the HRM-Pro, you can track advanced running metrics and swimming metrics when linked to a compatible smartwatch.
The running metrics sensor also enables the HRM-Pro to estimate lactate threshold; more precisely, using the Garmin HRM-Pro and a compatible smartwatch (e.g. Garmin Forerunner 745), the algorithm can determine the optimal pace you can run a 10K/half-marathon without completely exhausting the muscles. Perfect for runners who are not overly experienced in competition and would like to train at the correct pace. More on this here (opens in new tab).
The Garmin HRM-Pro can also connect to multiple devices simultaneously via Bluetooth and ANT+: you can feed heart rate data into your smartwatch and your Wattbike, all at the same time. Perfect for those athletes who like to track their performance in a million different apps.
This heart rate strap can also collect offline daily activity without a watch. Even if you aren't wearing a watch, maybe because you are charging it or you are performing an activity that requires you to take the watch off (e.g. kettlebell training), heart rate data will still be captured and fed into the Garmin Connect app continuously, as long as you are wearing the HRM-Pro.
Read our full Garmin HRM-Pro review
If you don't want to buy more than one heart rate monitor to track more than one type of sport, your best bet is on the Polar H10. It is the "most accurate heart rate sensor in Polar's history", and in fact, the Polar H10 can monitor your ticker very accurately.
The best thing is that the Polar H10 has built-in memory for one exercise, so you can wrap the heart rate monitor around your chest, start the exercise in the Polar Beat app and then leave the phone behind. The strap will sync with the phone once you are back home. More on this here (opens in new tab) (links to Youtube).
Polar H10 can connect to fitness apps, sports and smartwatches, and gym equipment using Bluetooth and ANT+ connection. Polar H10 can be connected to Bluetooth and ANT+ devices simultaneously so that you can hook it up with your watch and your turbo trainer as well at the same time.
The Polar H10 is also suitable for swimming, although it's not a dedicated swimming heart rate monitor. For the best results, you want to wear a tri-suit or wetsuit over it, so it is pressed closer to your skin as you swim.
The second-generation Tickr X has an integrated strap design, making it easier to put the sensor on, and the fit feels more secure. As soon as the monitor is on and picked up the heart rate (you might want to apply some water to the back of the strap for better connection), the LED lights on the top of the device start flashing, signalling it's ready to connect.
And the Wahoo Tickr X (Gen 2) connects fast: we tested it with our trusty Garmin Fenix 6 Pro, and it never failed to recognise the heart rate monitor within a matter of seconds (after the initial paring). The Tickr X can be paired to multiple devices simultaneously, so if you happen to use a smart trainer and a running watch simultaneously, the Tickr X will feed heart rate stats into both.
Runners will enjoy the new advanced running metrics: when paired with a GPS multi-sport or running watch, the ANT+ Running Dynamics will be broadcast on the Tickr X and recorded on the watch for real-time feedback. Should you decide not to use any other fitness wearables for your workouts, you'll be happy to hear that the Tickr X has built-in memory for up to 50 hours' worth of exercising, which can later be synced with the Wahoo App.
Much like the screen on running watches, the Wahoo App functions as the user interface for the Wahoo Tickr X heart rate monitor: you can see your profile and workout history, as well as check your stats in real-time as you exercise. The Wahoo App has 43 pre-configured profiles, and you can also switch out data screens with others, although it is worth mentioning that most screens are focused on either cycling or running metrics (obviously). So even if you do a 'gym workout' session, your average speed, distance and elevation gain will be recorded too. This is not a deal-breaker issue, however.
The Wahoo Tickr X is a premium heart rate monitor that provides a heap-load of useful features for runners, cyclists and other types of sportspeople. Maybe not for triathletes – it's only moderately water-resistant, but others prefer to work out on dry land.
Some fitness trackers and wrist wearables can already measure ECG – e.g. Withings ScanWatch and Fitbit Charge 5 – but the accuracy of these measurements is questionable. If only there were a heart rate monitor that measured ECG...
Well, there is one! Better still, the Frontier X tracks more than just ECG; it can track heart rate (obviously), cardiac rhythm, cardiac strain (similar to the Whoop 4.0) and even heart rate variability). As well as those, the Frontier X can also measure breathing rate and estimate training load, something called the Body Shock and step cadence.
Sounds good? It is good. The Frontier X provides endurance athletes with loads of data and recommends workouts based on previous sessions. It also assesses your workouts straight after they conclude via the Frontier X App, where you can analyse and overanalyse each and every activity you did wearing the heart rate monitor.
The app and the device mainly focus on training load and cardiac strain, so it's safe to say the Frontier X is best-suited for runners, cyclists, and other endurance athletes. It can track different types of workouts, of course, but the recommendations for strength athletes won't be quite as practical.
Sadly, no matter how large the head unit is, the Frontier X hasn't got built-in GPS, so you'll have to take the phone with you if you need distance data attached to your workout assessments. Alternatively, you can connect the Frontier X to watches and fitness machines via BLE (no ANT+, sadly), although it's too expensive to be used only as an external heart rate monitor.
On the upside, there is only this hefty lump sum to pay initially; using the Frontier X App is free, forever.
Verity Sense is a serious heart rate monitor for running, swimming, cycling and workouts, but it's also designed to be comfortable and easy to use. The latest from hardcore Finnish fitness brand Polar, it's one of the best heart rate monitors to date to use an optical sensor rather than the traditional electrical one.
That's why it doesn’t wrap around your chest but instead goes on your arm, which many people find more convenient. It can also attach to your swimming goggles to read your pulse from your forehead.
Boasting a host of additional fitness features, the Verity Sense has the potential to be a great alternative for those who find chest straps too clunky and smartwatches too unreliable: it's fantastically versatile, feature-rich, and well-priced heart rate monitoring strap – but you do have to contend with a not-so-user-friendly Polar Flow app.
We recommend using the Polar Beat app instead, which is way more user-friendly and feeds data back into the Polar Flow app. You can initiate a workout from the Polar Beat app and monitor heart rate and calories burned in real-time using the phone, which acts as an external screen for the Verity Sense strap.
You can also perform tests using Polar Beat, such as the Polar Fitness Test – a VO2 max assessment, basically. Although confusingly, these tests are found under the 'Upgrades' option. It's a bit odd having to use two apps to track your workouts successfully. We've seen worse, but Polar really should look to sort this out soon.
Read our full Polar Verity Sense review
The Myzone MZ-Switch is a super versatile fitness companion that will deliver accurate results during almost any workout. With exceptional battery life, a compact and lightweight design and an easy-to-use, feature-rich companion app, you can’t go far wrong here.
There is an ever so slight issue, though: the price. The MZ-Switch doesn’t look like it’s worth £140, nor is it the kind of device you’ll want to show off with pride due to its cheap-looking design, but it does the job it’s been designed to do very well, ensuring it’s ready for whatever sweat-inducing activity you throw at it.
In case you're unfamiliar, Myzone monitors use a different system than other heart rate monitors, the so-called MEPs system. Essentially, the Myzone MZ-Switch tracks which heart rate zone you're in and gives Myzone Effort Points (MEPs) after each workout.
MEPs are similar to all other gamified fitness reward systems, but at first, it can be a bit confusing to see a workout in the Myzone app composed of nothing but coloured lines. However, once you've got the hang of it, it's straightforward enough to use.
Peloton has its own shoes and apparel line, it's no surprise the most popular at-home exercise bike class provider sells a Peloton-branded heart rate monitor that seamlessly connects to the Peloton Bike+ and Peloton Tread.
The Peloton Heart Rate Band is exactly how you'd imagine a device capable of measuring heart rate from Peloton: it feels premium and looks kind of snazzy. It even comes in a fancy box that tells you little to nothing about what metrics the band tracks, nor the battery life.
What we know is that the Peloton Heart Rate Band is an armband that's meant to be worn on the forearm and measures heart rate and Strive Score (opens in new tab), which was launched in April 2021. Strive Score is a "personal, noncompetitive metric based on heart rate, and it measures how much time is spent in each heart rate zone to track how hard a person is working in every workout", Peloton explains.
Not sure if anyone would like to buy the Peloton Heart Rate Band as an external heart rate monitor but it can be used as one. It hasn't got ANT+ but the Band can connect to wearables via BLE. Sadly, it only really measures heart rate, unlike many other wearables in this guide, but if you need a comfortable external optical heart rate monitor to accompany your Garmin watch, you may as well consider the Peloton Heart Rate Band.
How to choose the best heart rate monitor for you?
Which heart rate monitor is best for you depends on the type of sport you do most often and on convenience factors, too. For example, there is no need to get a waterproof Garmin HRM-Swim when you hardly ever swim in a pool. At the same time, don't pick the Polar OH1 arm band if you don't want to charge/replace the battery in your heart rate monitor more than once a year.
When it comes to heart rate monitors, the cream of the crop at the moment is the Garmin HRM-Pro. It combines the best features of the Garmin HRM-Run and HRM-Swim and can be used both in and out of the water. It can also provide advanced running metrics and can be used without a watch too.
If you are after versatility, the Polar H10 is your best bet. It is very accurate as well as being waterproof and able to track heart rate under water. The Polar H10 has a 400-hour battery life, a single-activity memory and it also just comfortable to wear.
For runners, the best option is still the Garmin HRM-Run. Apart from tracking heart rate precisely, it also provides 6 extra running dynamics for the wearer – if it's paired with the correct device/app.
If you are after comfort, the Polar OH1 or the mioPOD arm bands are your best bet. They use optical sensors to track heart rate and have a much shorter battery life than their chest-strap counterparts; they can be worn on the upper/lower arm, making them less awkward to put on and remove.
If you are after ultimate precision, instead of just using good-old tap water, you can apply contact gel on the back of non-optical heart rate monitors, although it is a little bit of an overkill for most athletes apart from pros who need to track every minute change in their heart rate during workout sessions.
What's a good resting heart rate?
Resting heart rate – or pulse rate – is number of times your heart beats per minute (bpm) when you aren't active. This can vary widely from person to person and anything between 60-100 bpm can be considered 'normal' levels of resting heart rate, according to the British Heart Foundation (opens in new tab). Pulse rate varies throughout the day and tend to be the lowest at certain stages of sleep.
Athletes, especially endurance athletes, generally have a lower resting heart rate: young, healthy athletes can have a resting heart rate close to 40 bpm or even lower sometimes. The emphasis is on 'young' and 'healthy' as overworking your body, especially after a certain age, can have a detrimental effect on cardiovascular health.