Early Signal and Fitbit readiness
Fitbit’s readiness score is HRV, resting heart rate, and sleep. Skin temperature is a separate overnight metric.
Last reviewed 2026-09-24 · Sources · Editorial policy
01What the readiness score uses
Google’s help says the current readiness score is HRV, resting heart rate, and sleep—not yesterday’s activity, and not skin temperature. The first score needs about seven nights of wear. High, moderate, and low ranges are a recovery snapshot for the day.
02Skin temperature is separate
Compatible Fitbit devices and Pixel Watches can show sleeping skin-temperature variation against a personal baseline, often after a few nights. Google lists breathing rate, HRV, skin temperature, oxygen saturation, and resting heart rate as vitals, and notes that not every device records every metric. A temperature tile is not the same thing as the readiness number.
03How Early Signal weights the night
Early Signal is built around Apple Watch nights. Temperature and breathing lead when present; HRV and resting heart rate support; sleep is context. Status is Typical, Slightly off, or Off from usual, processed on device, with rare alerts. It does not read Fitbit accounts.
| Early Signal | Fitbit readiness | |
|---|---|---|
| Hardware | iPhone and Apple Watch. Does not read Fitbit accounts. | Compatible Fitbit and Pixel Watch devices. |
| Signals | Wrist temperature and breathing lead when present. HRV and resting heart rate support. Sleep is context. | The readiness score is HRV, resting heart rate, and recent sleep — not yesterday’s activity, and not skin temperature. Skin-temperature variation is a separate sleeping metric on supported devices. |
| Where it runs | Processed on the iPhone. | On the Fitbit or Pixel Watch. Not every device records every metric. |
| Status | Typical, Slightly off, or Off from usual, with rare alerts. | High, moderate, and low, after about seven nights of wear. |
| Limits | Wellness tool. Does not diagnose or treat disease. | This page does not rank the products. A temperature tile is not the readiness score. |
Guide FAQ
01Is skin temperature part of Fitbit readiness?
02Can Early Signal import Fitbit data?
Sources
Public documentation cited as context—not as clinical validation of Early Signal.
How it compares
Early Signal and Apple’s Vitals app
Both read overnight Watch metrics against your own range. They are different products with different jobs.
Compare
Early Signal and Oura Symptom Radar
Oura looks for strain from a ring. Early Signal looks for a personal pattern from the Watch you already wear.
Compare
Early Signal and WHOOP
WHOOP Recovery is a daily readiness score for strain. Early Signal is a rare wellness status from Apple Watch nights.
Compare
Related guides
Why a personal baseline beats population averages
Wellness scores that compare you to everyone hide the early personal shifts that matter.
Read
Poor sleep and feeling run down: what your Watch can and cannot say
A short night can move heart metrics. Sleep is context in Early Signal, not proof you need to stop.
Read
How accurate is Apple Watch wrist temperature?
Sleeping wrist temperature is a personal trend, not a clinical thermometer.
Read