Can I connect a Fitbit to an external heart rate monitor?

Have you ever wondered if you can connect a Fitbit to an external heart rate monitor? A Garmin, Polar and some other brands allow you to do this. Does Fitbit?

Why connect a Fitbit to an external heart rate monitor?

The obvious question is – why would you want to connect a Fitbit activity band or smartwatch to an external heart rate monitor. Most Fitbits these days have a heart rate sensor built-in.

Essential reading: Best fitness trackers and health gadgets

Well, as good as built-in heart rate monitors are, their accuracy is not on par with chest straps and armbands. At least, not yet. Numerous studies have confirmed this.

One of these was published by the Cleveland Clinic in Cardiovascular Diagnosis & Therapy. They found that the difference at rest was negligable. But the higher the intensity of exercise, the lower the accuracy of wrist-based heart rate monitors.

The reasons for this are numerous. But an important cause of inaccuracy when it comes to wrist-based heart rate measuring is that your arms are swinging. That’s even more the case at vigorous exercise. You arms swing making the tracker move up and down – hence accuracy suffers. Of course, you could tighten the strap and this will help a bit.

From all of this we can conclude that using a Fitbit to assess your resting heart rate is perfectly fine. As most people know, this is one of the most important health and fitness indicators. So it is a big deal having this metric every morning.

But for very high intensity exercise, using a wrist-based heart rate monitor is not ideal. So while a Fitbit may work for most people, those very serious about training may be better off with another solution.

Can I connect Fitbit to an external heart rate monitor?

Let’s get this out of the way at the start. There are no heart rate monitors that sync directly to a Fitbit. At least, not yet.

For whatever reason, Fitbit does not allow for direct communication between its fitness trackers and smartwatches with external sensors. Maybe because they see them as competition. And the company does not manufacture heart rate chest straps or arm bands of its own. Apple is similar. You cannot connect the Apple Watch to external sensors.

So it is not possible. There are smartphone apps that will sync exercise information to the Fitbit app from external sources for you. And this will sync over some of the data such as calories, but it will keep the heart rate data from the Fitbit device on your wrist.

There is a slight benefit to using a workaround solution. Even though the heart rate info will not sync, other info will. For example, calorie burn information will be ported over making this metric more accurate.

One way to do this is by using the MyFitnessPal app. This, for example, allows you to connect your Fitbit account to exercise tracked by Polar heart rate monitors such as the H10 or OH1.

Here are the steps:

When tracking workouts with the Polar chest strap or armband, you will need to start and end the workout in the Polar Beat or Polar Flow app. This information will then sync to MyFitnessPal. Which will complete the circle by syncing the exercise information over to the Fitbit app.

This is because when a user logs any type of cardio exercise on MyFitnessPal, this information is synced to their Fitbit account. Even if you enter the information manually. But, as mentioned, the heart rate data that will be the data from your Fitbit device.

You can add your voice and vote for the feature on the Fitbit Community webpages. There are requests sitting there for Fitbit to add compatibility with a Polar Chest strap and a separate thread asking for a Fitbit branded one. But they’ve been sitting there for a while. If you don’t want to wait and this feature is important for you, our suggestion is to go for a Garmin or Polar sports watch.

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