# Early Signal and Fitbit readiness

Canonical: https://getearlysignal.app/en/alternatives/fitbit

> Fitbit’s readiness score is HRV, resting heart rate, and sleep. Skin temperature is a separate overnight metric.

## In short

Google Health’s readiness score, on compatible Fitbit and Pixel Watch devices, combines HRV, resting heart rate, and recent sleep after about seven nights. Skin-temperature variation is a separate sleeping metric versus your baseline, not the readiness score itself. Early Signal leads with wrist temperature and breathing when Apple Watch has them, and scores on the iPhone. This page does not rank the products.

Last reviewed 2026-09-24

## What 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.

## Skin 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.

## How 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.

## Comparison

| | 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

### Is skin temperature part of Fitbit readiness?

Not in Google’s current description of the score. Readiness is HRV, resting heart rate, and sleep. Skin-temperature variation is its own Health metric on supported devices.

### Can Early Signal import Fitbit data?

No. It reads Apple Health from Apple Watch. A Fitbit or Pixel Watch is a different device.

## Sources

Public documentation cited as context—not as clinical validation of Early Signal.

- [Google Health — Understanding your readiness score](https://support.google.com/fitbit/answer/14236710)
- [Google Health — Skin temperature variation](https://support.google.com/fitbit/answer/14237207)
- [Google Health — Track your vitals](https://support.google.com/fitbit/answer/14236917)

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