How to Choose a Heart Rate Monitor

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Every runner can benefit from a heart rate monitor. Not only will you start to learn how to read your own body in terms of training and recovery, but you can also use the data to increase your performance by tweaking your training according to your heart rate.

If you have a smartwatch, chances are you already have a wrist-based heart rate monitor. Unfortunately, wrist-based heart rate monitors are not the most accurate, so if you’re looking for something to utilize for heart rate training, you may want to choose a different type.

In this guide, we’ll explain how to choose a heart rate monitor that suits your needs, and how to use it to boost your training.

What Is a Heart Rate Monitor?

A heart rate monitor—also known as an HRM—is a device that measures and records your heart rate in real-time.

The built-in electrical or optical sensors continuously detect each heartbeat and transmit the heart rate data to the receiver using Bluetooth or ANT+.

You’re able to view information like the number of beats per minute, calories burned, and time spent in different heart rate zones.

Depending on your device, you can view this data on your smartwatch display, phone app, or fitness wearable.

Who Can Benefit From a Heart Rate Monitor?

Athletes of any kind can benefit from the data that a heart rate monitor provides. The data provided by the HRM can lead to an increase in performance by allowing you to train in the optimal heart rate zone and make the most of your exercise sessions.

Other people who may want to invest in a heart rate monitor are those with heart problems or cardiovascular diseases. This will allow them to monitor their heart rate on a moment-by-moment basis and detect any changes that may be of concern.

How to Choose a Heart Rate Monitor

Type of HRM

Heart rate monitors come in a few different types, each with their own advantages and disadvantages. Let’s have a look at each one so you can make an informed decision.

Chest-Strap Heart Rate Monitors

This type of HRM features a small wireless sensor on a long, elasticated strap. It’s designed to fit around your chest with the sensor against your sternum.

A chest strap picks up the electrical signals on every heartbeat, which then translates into your real-time heart rate. This makes it very accurate, especially since it’s placed close to your heart.

Chest straps usually get a good fit on your chest making it hard to place the device incorrectly. However, you should make sure that it’s not placed upside down, as this can affect the accuracy.

The sensor on a chest strap is also unlikely to move much while you’re exercising, which increases its accuracy.

One of the biggest factors for a chest strap to work properly is that the strap needs to be wet. The moisture will help to pick up the electrical impulses more powerfully as water is an excellent conductor of electricity.

Sweat helps, but as it takes a while to start sweating, you will need to wet the strap before putting it on in order to get the greatest accuracy from the device.

You will also need to wash your strap and sensor thoroughly after each use, as the salt from sweat can build up and corrode the electrodes over time.

Chest strap HRMs work in conjunction with a receiver. You can’t view your data directly on the device, so you’ll need to pair it with your smartwatch or phone.

They usually also integrate seamlessly with apps like Strava or Garmin Connect.

Pros

  • High level of accuracy
  • Very easy to use
  • Easy to position correctly
  • Gets a good fit on the chest
  • Unobtrusive and easy to wear all-day

Cons

  • Some may find it to be uncomfortable
  • If there’s not enough moisture it will give you inaccurate readings
  • You need to clean your strap thoroughly after every use

Wrist-Based Heart Rate Monitors

Wrist-based heart rate monitors use LED lights with light-sensitive diodes to measure your heart rate. They’re placed near the pulse in your wrist making it fairly easy to measure.

They use a process called photoplethysmography. This shines a light on the skin and measures blood flow based on how the light reflects through the blood vessels on every beat.

Most smartwatches have a built-in heart rate monitor. But you are able to buy a standalone if you wish.

One of the bonuses of smartwatches is that they have their own display. There’s no need to buy a separate device if you have a smartwatch with an HRM function. In some cases—for example, the Whoop strap—you will still need a smartphone.

One of the issues with wrist-based HRMs is accuracy. The LED lights need to be tight against the skin in order to measure properly, which may cause discomfort. It can also measure less accurately on tattooed or darker skin.

Pros

  • Generally more comfortable than a chest strap
  • Convenient to have your HRM function built into your watch
  • Can be worn all day, every day for real-time tracking
  • Often include recovery and sleep data

Cons

  • Not as accurate as others
  • May not work as well on darker or tattooed skin
  • Tends to move more than a chest strap as you go about your day

Armband Heart Rate Monitors

Armband heart rate monitors are the newest type, but so far, research indicates that they may be the most accurate type.

They use the same light-based measuring process as wrist-based HRMs; however, the positioning makes the armband more accurate.

The sensor is usually placed on the inside of the bicep, against your brachial artery. Some armband HRMs place it on the forearm instead, just below the elbow.

This positioning is excellent for accuracy. The strap doesn’t move out of position as easily as a wrist-based HRM does, and the upper arm is not as susceptible to vibration as the wrist is. This means you’re reading won’t be skewed by outside influences.

Also, these types of heart rate monitors aren’t prone to stopping when the skin gets too dry, like chest straps are.

Pros

  • Known to be the most accurate of the HRM types
  • Stays in place even with a lot of movement
  • Vibrations don’t affect the reading
  • Easy to wear under clothing
  • Not affected by lack of moisture

Cons

  • May be uncomfortable for some people
  • Can be a little pricey

In-Ear Heart Rate Monitors

Some companies are beginning to incorporate heart rate monitor technology into their earphones, which is the newest kind of HRM technology but currently the least accurate.

They work the same way as wrist and arm-based heart rate monitors, by using light to measure blood flow.

These heart rate monitors come as part of the earphones. Currently, there are no standalone devices. You will also need a device to view your data, such as a smartwatch or a phone.

This technology is still being tested and updated as it’s very new, so if you’re looking for accuracy, this may not be the best choice.

Pros

  • Dual-purpose, with earphones and HRM in one device
  • Very little chance of the monitor moving during exercise

Cons

  • These can be quite a bit more expensive than others
  • Accuracy is up and down as the technology is still new
  • Not everybody is comfortable with an in-ear device

Key Features

Batteries & Battery Life

Decide whether you prefer rechargeable or replaceable batteries. If you choose an HRM with a replaceable battery, make sure that it’s easy to replace and you don’t need help from customer care or a service center.

The battery life should be good enough to comfortably see you through your main type of run. For example, an ultra runner will have different needs than a sprinter. The last thing you want is for your battery to die and your data not be recorded.

Digital Interface

Consider how you want to view your data. If you want to be able to view it during your exercise without pulling out your phone, ensure that you choose a heart rate monitor that’s compatible with your smartwatch so you can view your data in real-time.

If not, all you need to do is make sure it’s compatible with your phone and integrates with whatever fitness app you use. Most HRMs have their own phone app that you will need to download so they can store your data.

Tethering Options

Most heart rate monitors are compatible with both Bluetooth and ANT+ devices. However, you should double-check this before investing in one.

This is key if you decide to use a chest-strap HRM. Make sure it can sync with whatever device you are going to use it with.

Maximum Heart Rate

Most HRMS allow you to enter your variables like age, weight, etc. This will allow the device to calculate your maximum heart rate.

Alternatively, some devices will allow you to enter this manually. This will let you set your heart rate training zones.

High or Low HR Alerts

Many devices have an alert feature that sounds an alarm or a vibration when your heart rate exceeds a certain level.

You can usually set this to alert you when you’re out of your chosen training zone, or simply to let you know if your heart rate changes drastically when you’re at rest.

Target HR Zones

The more basic HRMs offer 3 target HR zones, while more advanced ones may have up to 6. Some heart rate monitors will calculate these zones for you automatically when it knows your maximum HR.

Many of them allow you to create your own workouts based on these zones—endurance, fat burning, etc. They will then alert you if your heart rate falls outside the parameters of your chosen target zone during the workout.

Time In Target Zone

Many heart rate monitors also track how much time you’ve spent in certain heart rate zones, both during a workout and overall.

Some specific goals—for example, fat burning—require a longer amount of time spent in a specific zone. This will allow you to structure your workouts to ensure that you’re spending the right amount of time in each HR zone to reach your goal.

Recovery Mode

This feature tracks how long it takes for your heart rate to return to resting after you’ve exercised. This is a great indicator of cardiovascular fitness.

Not only does this help you track your overall fitness improvements, but it also gives you an indication of how long you can expect recovery to take. This enables you to structure your workouts more effectively to prevent injury.

Calorie Counter

If you count calories, this will help you ensure that you’re burning more than you’re consuming—for fat loss—or maintaining. Calories burned also depends on your level of activity, and most HRMs come with this feature.

Record Lap Function

If you run on a track or swim, the ability to record laps is useful. Some HRMs offer this feature as well as lap times and the average heart rate per lap enabling you to compare and see where you may need to improve.

Speed and Distance Monitor

Just like regular fitness trackers, heart rate monitors also track speed and distance. This is handy if you have a distance-based goal or are working on improving your pace.

Comfort

Make sure you’ve chosen an HRM that will be comfortable for you. If you’ve never used a chest strap or armband before, be aware that it will take some time to get used to it.

It should also be unobtrusive for the activity that you’re doing. You want to be able to do your exercise without feeling like the HRM is irritating or in your way at any point during your workout.

Why Train With a Heart Rate Monitor?

Training with a heart rate monitor can take your performance to new levels. There are two primary reasons that using an HRM while training is a good idea, no matter what kind of training you’re doing:

Cater Your Training to Your Goals

Heart rate zones can be a powerful training tool. Exercising in different heart rate zones—at different intensity levels—helps you build particular areas of your fitness, like endurance or fat loss.

But being unaware of your heart rate can also have negative consequences. You could inadvertently overwork yourself, which leaves you open to injury and exhaustion.

Or, you could be exercising inefficiently and wondering why you aren’t seeing results.

Training with your heart rate monitor allows you to gain a good understanding of what zones you exercise in and make changes to your intensity as needed.

Everyone’s heart rate zones are different. This is based on your maximum heart rate, which you can calculate by subtracting your age from 220. For example, a 20-year-old’s max HR would be 200, while a 40-year-old’s would be 180.

For older athletes, the more accurate formula is 208 – (0.7 x your age).

Once you know this number, you can calculate your heart rate training zones. Each zone is based on a percentage of your maximum heart rate.

You can work out each of your zones by using this table. For example: if your maximum heart rate is 200, then each zone would be as follows:

Zone 1: 50 to 59% of 200 = 100 bpm to 118 bpm
Zone 2: 60 to 69% of 200 = 120 bpm to 138 bpm
Zone 3: 70 to 79% of 200 = 140 bpm to 158 bpm
Zone 4: 80 to 89% of 200 = 160 bpm to 178 bpm
Zone 5: 90 to 100% of 200 = 180 bpm to 200 bpm

Here’s how you should be using your heart rate zones to make the most out of your training for any sport:

This will allow you to optimize every training session to help you meet your goals faster and more easily. For example, if you want to lose fat, the fat burning zone is the place you should be.

Prevent Overtraining

Monitoring your heart rate and your HR zones can help you to structure your training in a way that allows you to both improve your performance and recover better.

For example, making sure to stick to zone 1 or 2 is best for the day after a hard zone 4 workout. Too many days in a high heart rate zone may not allow your body to rest enough to recover properly.

This could lead to you developing injuries, which could set you back especially if you’re training for a specific race or event.

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AUTHOR

Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.