How do skin temperature readings work?

[JLuluFitbit]

Hey Fitbit Community,

Your body tells a story while you sleep, and Fitbit captures this information by using a dedicated sensor to measure your skin temperature variation during sleep. This means it doesn't give you an exact skin temperature reading, but rather compares your temperature to your personal baseline.

Here's a breakdown of the process:

• Sensor: Fitbit Sense and Sense 2 use a dedicated sensor to estimate your skin temperature variation during sleep sessions. Fitbit Charge 4, Charge 5, Charge 6, Google Pixel Watch 2, Fitbit Inspire 2, Inspire 3, Luxe, and Versa series surface your sleep-measured skin temperature variation through existing sensors.

• Data Collection: For at least 3 nights, your device collects data to establish your personal baseline skin temperature. As you continue to wear your Fitbit device to sleep, the Fitbit app uses up to 30 days of data to adjust your baseline temperature.

• Comparison: After establishing a baseline, your device compares each night's skin temperature to this baseline.

• Variation:  Every morning, Fitbit then presents your skin temperature during the previous sleep from your baseline, indicating whether your skin temperature was higher or lower than usual.  

Note:

• Skin temperature variation, not core temperature: Fitbit measures skin temperature, which can be influenced by various factors like environment, sleep position, and even the device's placement on your wrist. It's not a direct measurement of your core body temperature.
  • Your skin's temperature can change a lot more than your internal body temperature. This is because your body uses your skin to help regulate its overall temperature.

• Baseline establishment: It takes 3 nights for Fitbit to establish your baseline skin temperature.
• Potential indicators: While not a diagnostic tool, by tracking these variations over time, you can observe patterns and potential trends in your sleep and overall health.

Important: If your temperature reading is unusually high or low, consult your healthcare provider to determine if it's normal and to get guidance on managing it. For immediate medical concerns, contact emergency services. Otherwise, reach out to your healthcare provider with any health questions or concerns.

For more information visit the Fitbit Help Center.

Your Fitbit Community Team