How does the Fitbit heart rate sensor work?

[LeticiaFitbit]

Hey Fitbit Community, 

Let’s take a look at how your tracker or smartwatch tracks your heart rate day and night and see tips to get a more accurate reading.

How does my Fitbit device detect heart rate?

Fitbit trackers and smartwatches use a technology called photoplethysmography (PPG) to measure heart rate. PPG works by shining a light through your skin and measuring how much light is absorbed. When your heart beats, more blood flows through your veins, which absorbs more light. Your tracker or smartwatch's sensor can detect these changes in light absorption and calculate your heart rate.

Fitbit trackers and smartwatches use a green light for PPG because it is absorbed well by blood. The sensor is located on the back of the device, where it is in contact with your skin. To get the most accurate heart rate reading from your Fitbit tracker or smartwatch, make sure that the device is snugly fitted on your wrist so that it doesn't move around while you're moving. You might also notice variations between your heart-rate reading on new Fitbit devices compared with your old ones due to changes in the heart-rate sensors themselves or algorithms.

How do I turn on heart-rate tracking on my Fitbit device?

Heart-rate tracking is turned on automatically. If you turned heart-rate tracking off, turn it back on:

On your device: 

• Open the Settings app  
• Tap Heart Rate 
• Tap to turn the setting On

On your Google Pixel Watch:

• Swipe left from the clock face until you reach the Heart Rate tile (The tile displays your current heart rate and a graph of your recent heart rate.) 
• Tap the tile to see more details in the Today app .

Note: You can’t turn off heart-rate tracking on Fitbit Sense, Fitbit Sense 2, Fitbit Versa 3, or Fitbit Versa 4.

Helpful links

Check out these help center articles for more details about Heart Rate tracking.

• How do I track heart rate with my Fitbit device?
• How do I improve the accuracy of a heart-rate reading?
• What factors can affect my heart-rate reading on my Fitbit device?

How often do you use the heart rate tracking feature on your Fitbit device? Join the conversation in the community!

The Fitbit team