# What is a normal HRV?

Canonical: https://getearlysignal.app/en/guides/what-is-a-normal-hrv

> There is no single healthy HRV number. The useful comparison is your own recent nights.

## In short

There is no single normal HRV. Healthy people differ by age, fitness, and how the watch samples the night. Apple Watch stores heart rate variability, often as SDNN. Early Signal ignores population charts and asks only whether last night moved versus your own median and spread. A low number versus someone else is not a status.

Last reviewed 2026-09-24

## Why charts of normal HRV mislead

Published ranges for heart rate variability are wide, and they mix different formulas. SDNN from a watch is not the same number as RMSSD from a chest strap or a ring. Comparing your Apple Health sample to a blog’s good HRV table mostly creates anxiety.

## What Early Signal compares

The app builds a personal median and MAD from your valid nights. Today’s HRV is a supporting signal: it can agree with temperature, breathing, and resting heart rate, but it does not set Off from usual by itself.

## What a drop can mean

Training, short sleep, alcohol, travel, stress, and feeling run down can all lower HRV. The app does not assign a cause. If you feel unwell, that matters more than the millisecond value.

## Guide FAQ

### Should I chase a higher HRV?

No. Early Signal does not treat a higher absolute HRV as healthier. It looks for an unusual drop versus your own usual range, and only as one supporting signal.

### Why does my friend’s HRV look so different?

Usual HRV is personal. Fitness, age, measurement method, and even the night’s sleep stage mix change the number. Their baseline is not your target.

## Sources

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

- [MedlinePlus — Heart rate variability](https://medlineplus.gov/ency/article/007200.htm)

## Privacy · Terms · Science

GetEarlySignal is a wellness tracking and rest-day support tool. It does not provide medical diagnoses, treatment plans, clinical assessments, or healthcare advice. The app does not replace professional medical care or emergency healthcare services.

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