Garmin heart rate guide: Features, devices and accuracy

The lowdown on tracking your heart with a Garmin watch or fitness tracker
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Heart rate monitoring has been a staple feature on Garmin's watches for some time now, but it's only over the last few years that it's taken the leap from getting that data from a paired heart rate chest strap to moving the tech directly into the wearables themselves.

Since Garmin launched the Forerunner 225 running watch back in 2015, its first device to include a built-in optical heart rate monitor, there's been a steady stream of sports watches and fitness trackers that now let you track heart rate activity from the wrist.

Read this: Best heart rate monitors to buy

But what kind of data can you see – and how can you make the most of those insights? We've broken down exactly how Garmin's heart rate technology works, the kind of data it provides and where you can find that information during and after your workout.

How does Garmin heart rate tech work?

Garmin heart rate guide: Features, devices and accuracy

So before we get into the data we need to talk about how that data is generated in the first place. Like many of the heart rate monitors found on watches like the Apple Watch or on Fitbit's wearables, Garmin takes a very similar approach across its devices.

It uses its own proprietary optical-based Elevate heart rate sensor technology. These sensors can be found on the back of Garmin's wearables – that way when they're strapped on, they're well positioned on the top of the skin to take a reading.

Unlike heart rate monitor chest straps, which measure the heart's electrical activity to produce HR data, optical heart rate monitors uses a series of lights that flash against the skin, illuminating capillaries in the body to detect changes in blood volume.

The sensor is then able to measure the rate at which blood is being pumped, giving you that heart rate data in real time.

Garmin watches with built-in heart rate monitors

Garmin heart rate guide: Features, devices and accuracy

Heart rate is standard across the Garmin range now, and there's no device that hasn't got one of the company's Elevate sensors inside.

So when choosing a device, it's not about whether you get heart rate – it's about how much data is gleaned from that sensor.

And that varies massively from device to device. You can check out our full rundown of the best Garmin watches here, but below is our at-a-glance guide to heart rate features.

Beginner's guide to choosing a Garmin heart rate monitor:

Basic info:

  • All Garmin devices
  • Vivofit 4
  • Forerunner 35

Pulse oxygen:

VO2 Max fitness level:

Advanced heart rate analytics

  • Fenix 5/6
  • Forerunner 245
  • Forerunner 645
  • Forerunner 945
  • Tactix
  • Quatix

Garmin heart rate: What does it track?

So we've established how Garmin's heart rate sensor tech works and outlined the wearables you can find it packed into. Now it's time to turn our attention to the heart rate driven data you can dive into.

Heart rate during workout

Garmin heart rate guide: Features, devices and accuracy

  • Found on pretty much all Garmin watches

But let's start with the one piece of data that everyone comes to expect, and that's real-time heart rate data when you're working out.

Whether you are going for a run, cycle or just having a general gym session, most heart rate sensor-packing wearables from Garmin will let you see this information displayed in BPMs (beats per minute), an indication of your workout intensity.

So why is this important? Well, knowing your heart rate can ensure you're working at the right intensity – making sure you're not slacking off, or more importantly, not burning yourself out on a rest day.

Check out our guide to HR training for more.

Garmin heart rate guide: Features, devices and accuracy

Heart rate zone data

  • Most Forerunner and Fenix devices

To view this information once you've started to track a workout, you can scroll through the data screens on your watch and you'll find a gauge like the one you can see above.

This displays your current heart rate zone – the zones all have different benefits depending on which one you spend the most time in. You can find out more about how it all works in our guide to training with heart rate zones.

If you prefer to see that real time heart rate data from one screen alongside another piece of real-time data (like distance or pace, for instance), you can customise data screens by heading into the settings of your device to change things up.

Post-workout heart data

  • All Garmin devices

Once you've finished your workout, you can review your data from the session. This will be found in the Garmin Connect app and will also be transferred into third party apps like Strava.

So what can you see? Well, you'll get a graph of your heart rate over the workout and an average and max HR figure. Checking your heart rate average is a good way of checking your performance against the intensity goal for the session.

If you are training by heart rate, you can monitor the average HR for a session against your speed. As your fitness increases, your speed will improve within the same HR zone.

Resting heart rate data 24/7

Garmin heart rate guide: Features, devices and accuracy

  • All Garmin devices

As well as using real-time heart rate data to keep a closer check on your workout intensity, many Garmins will now also let you monitor heart rate activity throughout the day and night.

You should look out for a screen that looks like the one above to check in on this data. What you'll see is a graph displaying resting heart rate readings picking out when it was at its highest and at its lowest. You should be able to view this over four hours and over seven days (image above).

Lowering resting heart rate is a sign of improving fitness – and for you hardcore athletes out there, you can learn when to take a day off if your RHR is around 10bpm higher than usual. This shows your body is stressed.

A low resting heart rate (40-60) is usually associated with athletes or anyone seriously into their training, but for most 60-100 is expected for the average adult. For many sports watches, that RHR data can be used in tandem with maximum heart rate to dictate heart rate based training zones.

Sleep tracking and heart rate data

Garmin heart rate guide: Features, devices and accuracy

  • Sleep tracking on all Garmin devices
  • Pulse ox only on Vivoactive 4/Vivosmart 4/Fenix 5/Fenix 6/Forerunner 945

Like a lot of wearables, Garmin's watches and fitness trackers are better equipped to monitor what happens when you're not working out. We're talking about sleep time.

Monitoring that sleep is done using the motion sensors inside of the device detecting when there is no movement to kickstart the sleep tracking. The addition of a heart rate monitor has improved that ability to better analyse your sleep time to and breaking down when you've had good quality snoozing.

Garmin is now using heart rate variability measurements to improve the accuracy of determining the time you've spent awake and the time you've spent in specific sleep stages. Those sleep stages are: light sleep, deep sleep and REM (rapid eye movement) sleep.

VO2 Max estimates

Garmin heart rate guide: Features, devices and accuracy

  • Forerunner 45 (not shown on watch)
  • Forerunner 245
  • Forerunner 645
  • Forerunner 945
  • Vivoactive 3/4/4S
  • Venu
  • Marq
  • Quatix

This piece of heart rate based piece of data is definitely one for fitness fans.

It relates to the rate the heart and lungs can transport oxygen to muscles to measure your aerobic fitness level.

The idea is that as you get fitter, your VO2 Max score should get higher. It's one of the best metrics for tracking your data.

In the case of Garmin's wearables like the Forerunner 945, your VO2 Max score is represented on a colour coded gauge and is designed for runners and cyclists. You will need to have run outdoors with GPS tracking or cycle with a power meter for several minutes to produce the estimate.

The breakdown of the colours is as follows:

Red – Poor

Orange – Fair

Green – Good

Blue – Excellent

Purple – Superior

Recovery time

Garmin heart rate guide: Features, devices and accuracy

Recovery tracking Garmin devices

  • Forerunner 245/645/945
  • Fenix

Garmin's top end wearables can also provide an insight into whether you need to take a day off before you start training again, using heart rate data from your wrist or a paired heart rate monitor chest strap.

This insight relies on your VO2 Max scores we described above, so it may take a few tracked workouts before you start seeing accurate, reliable data.

There's two ways to view your recovery time.

Firstly, it will be displayed after you've logged and saved a tracked run. Or post session, you can hunt out the performance widget on your watch, which will display a recommended recovery time and intensity level for that next workout.

Recovery heart rate

  • Forerunner 245/645/945
  • Fenix

Another one reserved for Garmin's more capable sports watches, recovery heart rate is based on a reading of your heart rate during exercise and two minutes after the exercise has stopped. The difference between those two readings gives you your recovery heart rate. The optimal way to get this reading is to stop moving completely after that workout to improve the reliability of the information.

Why is recovery heart rate important? According to Garmin, studies have shown that recovery heart rate data can be linked to cardiac health. If you score a higher number, that's a good indication that you have a healthy heart.

Training Effect/Load

Garmin heart rate guide: Features, devices and accuracy

  • Forerunner 245/645/945
  • Fenix
  • Tactix
  • Quatix
  • Marq

If you're wondering whether doing two big runs two days in a row is a good thing (it's probably not a good thing), Garmin's Training Effect feature is all about measuring the impact of aerobic and anaerobic training on your body.

Some of Garmin's wearables measure both forms of training, while others will just offer insights into one. It uses heart rate data along with the duration and intensity of your activity to provide the training effect data.

You'll then be presented with a colour code, training effect number and an aerobic and anaerobic benefit insight. These insights tell you whether that workout has been good for maintaining your fitness levels.

So it could say the session highly improved your fitness, or that you didn't give yourself enough recovery time before working out again.

Lactate Threshold (with chest strap)

A hugely insightful mode, LT finds the pace and HR at which your body crosses into a state where lactic acid can no longer be removed by the body. You'll know this as the difference between a gentle easy run and a hard workout.

This data can be used to inform your HR zones and make for a much more reliable workout. If you run with a chest strap this will be logged, and you can do a test.

Be aware it will ONLY work with a connected chest strap in an outdoor, GPS tracked workout. You must also have some VO2 Max data logged.

  • Forerunner 645/945/735XT
  • Fenix 3/5/6
  • Tactix
  • Quatix
  • Marq

Stress tracking

Garmin heart rate guide: Features, devices and accuracy

  • Forerunner 645/945
  • Fenix 5/6
  • Tactix
  • Quatix

This a relatively new feature for Garmin's stable of wearables, which kicked off with the Vivosmart 4 before rolling out to watches like the Fenix 5 series and top end Forerunner watches.

Now your Garmin can tap into your heart to get a better indication of your stress levels throughout the day. It uses heart rate variability to provide this information.

HRV relates to the measurement of the time interval between heartbeats. Unlike measuring heart rate, which is about the average number of heart beats per minute, HRV focuses on the small fluctuations of the heart. A number of things can impact on these readings including age, time of day and health.

For those Garmins that do support stress monitoring, you should look for the screen above, which shows an indication of your stress level in real time with a numbered score, which ranges from 1-100. 1 means low stress and 100 means, well, you should probably do something to relax.

You'll also be able to see your stress scores across a four hour period to help identify whether there was a particular event that may have caused your stress levels to spike.

HRV stress test

Garmin heart rate guide: Features, devices and accuracy

  • Forerunner 645/945
  • Fenix
  • Quatix
  • Tactix
  • Marq

There is another way that Garmin taps into heart rate variability to offer insights into your stress, training, nutrition and everyday life stress. Unlike the stress tracking feature mentioned above, this feature requires pairing your wearable with a compatible heart rate monitor chest strap.

Once you get hold of one of those, you'll need to spare three minutes to measure HRV and be standing still to get a reliable reading.

Then you can make a better call over whether you should be planning an intense HIIT workout, or maybe just relax. If you're struggling to find the HRV Stress test, it can be found in the same place where you can start tracking an activity on your Garmin wearable.

How accurate is Garmin heart rate data?

While many people might think that having a heart rate monitor on their wrist means accuracy is a given, a lot of the data here is assumed from details you put in at the start.

Max HR is calculated by using 220 - age, and your zones estimated from there, for example.

Garmin does have the power to adjust these on real-world data.

However, you'll find that running with a chest strap will improve on this data-set. So even if you train with the optical (which is pretty accurate at medium intensity), it's worth hooking up a chest strap for the odd high-intensity session.

How to set your own heart rate zones

If you know your heart rate zones, for whatever reason, they can be manually entered into Garmin Connect:

  • Open Garmin Connect app
  • Open the Menu
  • Tap Garmin Devices
  • Choose device
  • Tap User Settings
  • Tap Configure Heart Rate Zones
  • Enter the lowest heart rate value for each zone

Add an external chest strap

Most Garmin Forerunner devices enable you to add an external heart rate strap, which will offer better accuracy and lower lag time than an optical sensor. What's more, some features such as HRV Stress are only accessible with a chest strap.

Garmin supports ANT+ sensors – and you don't have to use the company's own. Each device slightly differs on how to install them, but the vague premise is the same:

1. Put on the heart rate monitor.

2. Bring the Garmin watch near the strap. You may need to jump around a little or walk just to power up the sensor.

3. Go to the Garmin's menu > Settings > Sensors and Accessories. If it's the first time, choose Add new sensor > External Heart Rate Monitor. Once paired, your watch will remember the connection.

Review heart rate data on Garmin Connect

Garmin heart rate guide: Features, devices and accuracy

Garmin has made it pretty easy to review heart rate data on the wrist. It also does a very good job crunching the numbers and doing the analysis, saving you the headache of working out what it all means.

Read next: In-depth guide to Garmin Connect

Sometimes though, it's nice to sit down, grab your phone or laptop and soak up the data on a bigger screen. Fortunately you can do that from the Garmin Connect app and we're going to show you where you need to go to find that data.

Garmin heart rate guide: Features, devices and accuracy

The good news is that Garmin's revamped Connect app now puts daily heart rate data and stress data front and centre. Head to the My Day tab and you should see resting and high rate up top.

Tap on either the heart rate or stress tabs and you can drill in to that data further. What you'll see is a graph of your day, logging key events during the day (image below) and plotting heart rate data throughout the day. This way you can start to identify whether certain events have created a spike in your heart rate.

Garmin heart rate guide: Features, devices and accuracy

The calendar tab will let you jump from different days to see daily data, with a red bar indicating a full day's worth of heart rate data has been recorded.

Look for the dropdown menu in the Connect app (top left corner), where you'll find a section dedicated to Health Stats. This is where you can view All-Day Heart Rate over seven days, a month and a year, giving you resting and high HR averages. You can also find performance stats including VO2 Max, Training Effect and HRV Stress data.

Another important area to pay attention to is finding the place where you can configure your heart rate zones for heart rate based training. Tap on the icon displaying your Garmin wearable and head to User Settings to adjust zones.

And that is our comprehensive overview of getting to grips with heart rate monitoring on a Garmin. Got any questions about anything above? Let us know in the comments section below.

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Michael Sawh


Michael Sawh has been covering the wearable tech industry since the very first Fitbit landed back in 2011. Previously the resident wearable tech expert at Trusted Reviews, he also marshaled the features section of

He also regularly contributed to T3 magazine when they needed someone to talk about fitness trackers, running watches, headphones, tablets, and phones.

Michael writes for GQ, Wired, Coach Mag, Metro, MSN, BBC Focus, Stuff, TechRadar and has made several appearances on the BBC Travel Show to talk all things tech. 

Michael is a lover of all things sports and fitness-tech related, clocking up over 15 marathons and has put in serious hours in the pool all in the name of testing every fitness wearable going. Expect to see him with a minimum of two wearables at any given time.

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