Heart Rate Not Reading
Fitbit Fitness Tracker / Smartwatch
Severity: ModerateWhat Does This Error Mean?
Your Fitbit is not recording heart rate data, or readings show gaps and dashes. Fitbit uses an optical sensor on the back of the device — it needs firm skin contact and a clean surface to work. Fit, cleanliness, and wearing position are the most common causes of missing heart rate data.
Affected Models
- Fitbit Charge 6
- Fitbit Versa 4
- Fitbit Sense 2
- Fitbit Inspire 3
- Fitbit Luxe
Common Causes
- Heart rate tracking is disabled in the Fitbit app settings
- Fitbit is worn too loosely
- Sensor on the back is dirty or covered in sunscreen or lotion
- Device worn too close to the wrist bone
- Tattoos on the wrist interfering with the optical sensor
- Cold hands reducing blood flow to the wrist
How to Fix It
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Verify heart rate tracking is enabled: Fitbit app > your device tile > Heart Rate > select 'On' or 'Auto'.
Fitbit allows you to disable heart rate tracking to save battery. Make sure it is set to On or Auto, not Off.
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Tighten the band and move the device one finger-width above the wrist bone.
The optical sensor needs consistent skin contact. A loose Fitbit bounces with movement, creating gaps in heart rate data.
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Clean the back of the Fitbit with a damp cloth and let it dry completely.
Lotion, sunscreen, and sweat coat the sensor window and reduce light transmission. Clean the sensor and wrist before wearing.
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Restart the Fitbit by pressing and holding the button for 8–10 seconds.
A software issue with the heart rate service is cleared by a restart. After restarting, check if heart rate begins recording.
When to Call a Professional
If heart rate consistently shows zero even when worn correctly on a clean, warm wrist — and a restart does not help — the optical sensor may be damaged. Contact Fitbit Support for a warranty assessment.
Frequently Asked Questions
Why does Fitbit show dashes instead of my heart rate?
Dashes mean the sensor cannot get a confident reading. This is almost always a fit issue — wear the Fitbit snugly, one finger-width above the wrist bone. Stay still during a manual reading for best results.
Should I wear Fitbit tighter during exercise?
Yes — Fitbit recommends wearing the band slightly tighter during exercise than during rest. Tighter during exercise reduces motion artifacts from arm swing and gives more accurate continuous heart rate readings. Loosen it slightly after your workout for comfort.