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How Accurate Is Fitbit Heart Rate? (What You Should Know)


Featuring a built-in heart rate monitor, Fitbit Charge 5, Versa 3, and Sense can easily gauge your heartbeat during any activity, including intense workouts and sleep. But how accurate is Fitbit heart rate in the first place?

Your Fitbit’s heart rate may not be as accurate as equipment used in healthcare facilities. But the estimates you get are highly likely to be enough for your needs. For example, Fitbit Charge 2 guarantees an estimated accuracy of about 90% in testing, especially during resting and light workouts.

Fitbit continues to better its products, with every new release being much better than the first. Its latest models, such as Fitbit Charge 5, Sense, Luxe, and Charge 4, perform quite well at measuring heart rate.

And while the data can’t be 100% accurate compared to the electrocardiograph technology, the results for active and resting heart rate can be quite useful.

Which Fitbit Has the Most Accurate Heart Rate?

The latest Fitbit models monitor heart rate more accurately compared to the older ones.

Fitbit Luxe a wrist-based fitness tracker with 120 hours battery life features an optical sensor that track your heart rate. From this, you get total calories burned, not to mention you even get to look at your breathing rate.

The latest Fitbit Charge 5 equally has a built-in heart rate sensor that monitors your HR more accurately the Alta HR. 

How Accurate is Fitbit Heart Rate?

Fitbit HR by The Quantified Scientist

Fitbit models Luxe, Versa 3, Sense, and Charge 5 have taken the niche market by storm, and for a good reason. Fitbit invests in innovative technology and in-depth testing to make sure it’s devices are as accurate as possible.

But can you merely conclude that Fitbit’s heart rate is 100% accurate?

In testing, the built-in heart rate sensor proves quite solid, with the overall results being accurate for health and activities.

In comparison to chest strap sensors, Fitbit returns more heart rate data when tracking bike rides and running. Even the resting and walking heart rate have a higher level of accuracy in real-time.

Keep in mind though that your Fitbit device will experience a fluctuation between high and low heart rate during workouts, with the overall accuracy rate going down as you increase your exercise intensity from moderate to high.

The variation in the numbers is a reasonable case for the inaccuracy of the sensors built into Fitbit devices.

In other words, optical sensors aren’t 100% perfect yet, so it makes sense why you might see a fluctuation in results in the first place.   

Can Fitbit Get Heart Rate Wrong?

I started this guide by stating clearly that your Fitbit’s heart rate monitor won’t be as accurate as ECG devices.

And while that holds true even for other smartwatch and fitness tracker brands, the results you get can be substantial.

But Fitbit can get heart rate wrong sometimes.

In an article published by CNN News, Fitbit heart rate isn’t as accurate during moderate to high intensity exercises as it is when a user is at rest.

The study shows that the heart rate technology built into smartwatches and fitness trackers has a long way to go to be as accurate as ECG equipment.

One reason in particular is that the LED technology built into a fitness tracker targets indirect measurements of the changes in light reflection through the skin with every heartbeat.

To be clear, the occasional flop in heart rate reading doesn’t make Fitbit devices as dangerous as some online media would want you to believe. In fact, Fitbit has been fine-tuning its devices, making each new release better at tracking fitness stats than the previous debuts ever did.

As it stands, Fitbit’s Pure Pulse technology works well within the industry standards for wrist-based heart rate monitor, with an average error of at most 6%. 

How Do I Make My Fitbit Heart Rate More Accurate?

Fitbit can get your heart rate data right or wrong depending on how you wear your smartwatch or fitness tracker.

So to make your Fitbit heart rate more accurate, you need to wear your Fitbit such that it touches the skin.

The device should feel snug. It should not be too loose, or the sensor may fail to make contact with your skin, resulting into inaccurate results. And it shouldn’t be too tight or the Fitbit might hurt your wrist.

When you have this wrist-based monitor just tight enough on your wrist, light from the sensors won’t leak from the side and therefore the tracking signals will do their job accordingly.

Fitbit positioning is also an important factor to consider if you must make your heart rate’s reading accurate.

Unless you’re resting, you should wear the device higher on your wrist. At this position, your smartwatch or fitness tracker can get reliable readings, even when your arms move more frequently.

Frequently Asked Questions

1. Can You Turn Off Heart Rate Monitor on Fitbit?

It’s easy to turn off the heart rate monitor on your Fitbit device. 

You just have to turn on your device, and swipe to access the settings option. Then, scroll down until you see heart the heart rate. Tap on the option to turn it off.

2. What is a Good Fitbit Resting Heart Rate? 

A good Fitbit resting heart rate is between 60 and 100 beats per minute for adults. You’re completely healthy, with your heart working optimally if you have your rate falling within this range.

3. Why Does My Resting Heart Rate Fluctuate On My Fitbit?

Your resting heart rate won’t be constant on your Fitbit all through. That’s because factors such as stress levels, caffeine intake, movements, humidity, and temperature can easily affect the results that you get for your HR.

Note that the fluctuation in your heart rate is something completely normal.

4. When Does Fitbit Heart Rate Monitor Perform Best?

You’re highly likely to get accurate HR reading from your Fitbit when you’re at rest and when doing light exercises.

Unfortunately, the device might underestimate your HR results when performing moderate to highly intense workouts.

Keep this in mind when using your Fitbit device for heart rate monitoring.

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Final Thoughts

Fitbit makes some of the best fitness trackers and smartwatches, and they have millions of active users to show for it.

However, your Fitbit device won’t track your heart rate with 100% precision all the time. You might notice your model underestimating the results, particularly during intense workouts.

The bottom line is that if you’re going to use a Fitbit to track your fitness, just be aware that the device won’t give you precise results all the time.

Note that newer Fitbit models such as Charge 5, Sense, Versa 2, and Luxe are more monitor heart rate more accurately than the likes of Alta HR and the original Charge.

One last thing that I would like to state is that while Fitbit heart rate won’t be 100% accurate, the data you get can still be useful in helping you know about your overall heart health.

And who knows, Fitbit just might get its heart rate monitors 100% accurate with continued research, improvements in its technology, and invention and implementation of new features.  

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Michael Jonathan

Michael Jonathan is the brainchild of Apelo Studio. He loves talking about wearable devices, and he is passionate about helping you push your wearable device to its limits. His creativity and ability to tear electric components apart and put them back together makes him an incredible troubleshooter and blogger.

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