Even in 2021, the best heart rate monitor tracks heart rate more accurately than the best running watch. For those athlete who take training seriously, heart rate sensors are a must, whether it's the chest strap or the armband variety. 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 tracker safely and precisely using wrist wearables.
For many, tracking heart rate on the wrist with a fitness tracker or running watch might seem sufficient enough but precise readings from wrist-mounted optical heart rate sensors can be compromised by a lot of external factors: the wrist moving too much, sweat, hair on the wrist and so on.
Heart rate monitors provide more accurate readings than wrist-mounted optical heart rate sensors. Even the best optical heart rate sensors, like the Garmin Elevate or the Polar Precision Prime sensor, can only be so accurate when you wriggle your wrist around, getting sweaty, things you do often when you exercise. Once the fitness watch loses contact with your skin, readings will be less accurate or just plain wrong altogether.
Heart rate monitors, especially the chest strap variety, provide more accurate heart rate tracking for two reasons: they don't have to 'see' your skin like optical sensors, and the elastic strap the sensor is mounted on also fits the torso better.
Some wearables such as the best triathlon watches, can measure heart rate under water but just like during running, you'll get more accurate results wearing a water-resistant heart rate monitor. If you are planning on upgrading your running gear, make sure you check out the best running shoes and best running headphones guide too.
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.
Best heart rate monitors, in order of preference
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 but also 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 with the correct pace. More on this here.
The Garmin HRM-Pro can also connect to multiple devices at the same time 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 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.
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, 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.
Polar H10 can connect to fitness apps, sports and smart watches, gym equipment using Bluetooth and ANT+ connection. Polar H10 can be connected to Bluetooth and ANT+ devices simultaneously, so you can hook it up with your watch and your turbo trainer as well in the same time.
The Polar H10 is also suitable for swimming, although it's not a per-se swimming heart rate monitor and 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.
As for comfort, the Polar H10 is equipped with the Polar Pro strap that sports a range of little non-slip dots along the inside of the belt. These help the belt stay in position without making it feel to synthetic.
The Polar H10 heart rate monitor also supports Polar's Orthostatic test that records your heart rate variability and "equips you with knowledge about your recovery as well as tools to optimise your training." You will need a Polar Vantage V or Vantage M to do this test, mind.
Wahoo went the extra mile in 2020 to update the already popular Wahoo Tickr X heart rate monitor. The second generation Tickr X has an integrated strap design, making it easier to put the sensor on and the fit feels more secure too. 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: I tested it with my trusty Garmin Fenix 6 Pro and it never failed to recognise the heart rate monitor within the 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 at the same time, 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 checking 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 premium heart rate monitor that provides a heap-load of useful features for runners and cyclists but also for other types of sportspeople too. Maybe not for triathletes – it's only moderately water resistant – but others who prefer to work out on dry land.
It seems that majority of runners wear a Garmin running watch nowadays, so getting the Garmin HRM-Run is probably the best option for them. As the name suggests, the Garmin HRM-Run works best for runners and will provide advanced running metrics and precise heart rate readings on land. It is waterproof as well.
There are six different metrics being measured by the Garmin HRM-Run: cadence, vertical oscillation, ground contact time, ground contact time balance, stride length and vertical ratio. If none of these make much sense to you, you'd probably want to hold off before you get the Garmin HRM-Run.
As you'd expect, the Garmin HRM-Run can make you a more efficient runner, but only if you are keen on learning and adjusting your technique. It won't run better for you but will provide you with ample amount of data so you can analyse your running form in minute details.
Battery life is up to a year – there is no screen or optical sensors involved after all – and the Garmin HRM-Run supports both Bluetooth and ANT+ connections too. The strap supplied with the product is comfortable enough and won't chafe your skin.
Most importantly, the Garmin HRM-Run can be used – with a compatible Garmin watch – to perform a lactate threshold test. From Garmin's website: "Lactate threshold is the point where your muscles start to rapidly fatigue. Your device measures your lactate threshold level using heart rate and pace.
When a runner exceeds their threshold, fatigue starts to increase at an accelerating rate. For experienced runners, the threshold occurs at approximately 90% of max heart rate corresponding to a pace somewhere between 10K and half-marathon race pace. For the average runner it occurs well below 90% of their maximum heart rate. Knowing your lactate threshold can help you determine how hard to train or when to push yourself during a race."
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 to 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.
• Read our full Myzone MZ-Switch review here
The Garmin HRM-Swim was designed for water based workouts. But unlike the Garmin HRM-Tri, the HRM-Swim can be used in pools as it is pool chemical resistant and comes with a non-slip strap that stay in place even as you kick yourself off the wall of the pool as you turn.
The Garmin HRM-Swim truly is a poll-swimmer's wet dream: it stores and forwards heart rate, measures swim interval heart rate statistics, so you can have a much better understanding of how well you perform under water.
Of course, many other heart rate sensors are also water resistant, but there is a huge difference between a heart rate monitor unit being watertight and it being capable of accurately monitoring heart rate under water. As you may know, water is highly conductive and this property can skew heart rate readings significantly.
Using the Garmin HRM-Swim, you can make sure your heart rate is actually what it says in the app/watch, not just an approximate calculation.
The downside of the Garmin HRM-Swim is that it really is for swimming; it can be used on land, but for that purpose, you have devices that are cheaper and provide more land based metrics. If you swim in a pool often, however, you should definitely get the Garmin HRM-Swim.
One thing that often doesn't come up in the conversation is just how unpleasant it is to put on a cold chest strap during the winter months. When you are cold as it is, wrapping a cold and wet strap around your torso is not a sensation many will yearn after.
The Polar OH1 armband is an ideal compromise between precision and comfort: the optical heart rate sensor will provide accurate readings than a running watch. Why, you ask? Although the Polar OH1 and a running watch may both use the same type of sensors, but since the armband sits better on your skin, it will be able to pick up signal more easily and accurately. Your wrist twists and turns all the time and it is not hard for a watch to lose connection to your skin there.
On the downside, the Polar OH1's optical sensor does eat up battery life way more than its traditional counterparts and will 'only' last for 12 hours between charges. This is 12 hours of exercising, mind, so you still won't need to use the charger more than once every other week, but compared to the 1-year battery life of chest straps, it's still much shorter.
The Polar OH1 has a swimming goggle strap clip so you can thread the clip to the strap of your swimming goggles. The Polar OH1 will stay snug against your temple and give you good heart rate readings, even under water.
The mioPOD heart rate monitor – paired up with the accompanying mioApp – is trying to bridge the gap between a passive heart rate sensor and a running watch. It still is a heart rate sensor, not a chest strap but an arm band, much like the Polar OH1, but with some added perks: it has haptic feedback and also visual feedback on heart rate zones.
The latter feature is called Cardio Pilot and it alerts you if you go from one heart rate zone to the other. The haptic feedback helps you notice these changes, even if you are not staring at the mioPOD as you workout. The mioPOD is mainly a good weather/indoor heart rate monitor: it would be hard to work out what the haptic feedback is about if you are wearing a base layer, a jumper and a jacket over the sensor.
The Valencell optical sensor used in the mioPOD is precise and you can also check your heart rate in real-time using the mioApp. The app is okay to use although not the most intuitive compared to the Fitbit App or Garmin Connect. It does have a workout memory, so does the mioPOD which can store 30 hours-worth of workouts.
The mioApp also has a couple of decent fitness features, like measuring training load (just like Garmin) and recovery status (much like Polar). In the app, you can also see how many calories you burned and even advanced running metrics like cadence. The mioPOD is also swimproof.