# Apple’s Vitals app, explained

Canonical: https://getearlysignal.app/en/guides/apple-watch-vitals-app-explained

> What the built-in Vitals app shows overnight, and how that differs from Early Signal.

## In short

Apple’s Vitals app, on the Watch, shows overnight metrics against a typical range it learns from your sleep: heart rate, respiratory rate, wrist temperature on Series 8 and Ultra, blood oxygen where available, and sleep duration. It can notify you when multiple metrics sit outside that range. Early Signal is a separate iPhone app that reads Apple Health, adds HRV as support, and turns the night into Typical, Slightly off, or Off from usual—on device, and not a medical device.

Last reviewed 2026-09-24

## What Vitals shows

Apple’s support article lists overnight heart rate, respiratory rate, wrist temperature, blood oxygen, and sleep duration. You wear the watch to sleep so it can establish a typical range—Apple says about seven nights. Outliers are marked against that personal range, not against a population chart.

## When it notifies you

By default, Vitals can notify you when multiple overnight metrics are outside your typical range, and it offers context for factors that can be involved. That is Apple’s own view of the night. It is not a diagnosis.

## Where Early Signal is different

Early Signal runs on the iPhone, on device, from Health samples you already have. It treats wrist temperature and breathing as lead signals, HRV and resting heart rate as support, and sleep as context. Status is Typical, Slightly off, or Off from usual, with alerts capped. It does not replace Vitals. It is a wellness tool: it does not diagnose or treat disease, and it is not medical advice.

## Guide FAQ

### Do I need both?

No. Vitals is built into a compatible Watch. Early Signal is optional if you want a separate on-device status from the same Health data, including HRV as a supporting signal.

### Does Vitals include HRV?

Apple’s Vitals support article lists heart rate, respiratory rate, wrist temperature, blood oxygen, and sleep duration. Early Signal reads HRV from Apple Health as its own supporting signal.

## Sources

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

- [Apple — Track your overnight vitals with Apple Watch](https://support.apple.com/en-us/120142)
- [Apple — Track your nighttime respiratory rate](https://support.apple.com/en-us/HT211027)

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