# Overnight respiratory rate (RR)

Breaths per minute in sleep, stable for a person. Rises with fever and heavy training.

Type: biomarker · Unit: breaths/min · Domain: Cardio-Respiratory Health · Accuracy: Trend-grade · Importance: Core

Also called: breathing rate, respiration rate, breaths per minute, overnight breathing

## In one sentence

How many breaths you take a minute while asleep, read by your ring or band from the rhythm of your pulse rather than from your chest.

## Why it matters

Breathing rate at rest is one of the steadiest things about a person: it is set by the body's demand for oxygen and its need to clear carbon dioxide, and neither changes much from one quiet night to the next. That steadiness is what makes it useful. When the body is fighting something, the demand rises and so does the rate, which is why respiratory rate is a main reading in Symptom Radar. In 2,745 people with a confirmed respiratory infection who wore a wrist tracker, respiration rate and heart rate were typically raised and HRV lowered in the days around diagnosis (Natarajan 2020).

## What moves it

Upward: a fever or an infection, a hard training day, heat, altitude, a heavy late meal, alcohol, anxiety, pregnancy. Downward: not much, which is why Symptom Radar watches it in one direction only. Sleep-disordered breathing changes its pattern more than its average; a wearable's single figure is not a way to look for that, and a doctor's sleep study is.

## How to measure it well

The same device every night. The number is derived from the pulse wave, which carries the breath as a slow rise and fall, so the device needs a clean overnight signal: a snug ring or band and a charged battery do more for this reading than for any other.

## How Vitality Tracker uses it

A main reading in Symptom Radar (weight 1.0, higher is the direction it watches), compared with your own 30-day baseline, with sick days and the three after them left out. Symptom Radar does not yet start a new baseline for this reading by itself when you change device, so expect a few unsettled nights after a switch while the baseline catches up. Once Symptom Radar is running, a night below 8 or above 25 breaths per minute adds a safety note to the morning's result, whatever your baseline.

## How far to trust the number

Trend-grade. The rate is estimated from the pulse, not counted at the chest, and the published checks of ring and wrist estimates against laboratory counts are device-specific and few; VT therefore reads it only against your own nights, where a steady baseline makes even a small rise visible. The level is the device's; the change is yours.

## Method

The device extracts the breathing rhythm from the beat-to-beat timing and the baseline wander of the optical pulse signal during sleep and reports the night's average. Stored as the overnight respiratory rate; baseline and comparison as for the other main readings.

## Sources

1. Natarajan A, Su HW, Heneghan C. Assessment of physiological signs associated with COVID-19 measured using wearable devices. NPJ Digit Med 2020;3:156. [doi:10.1038/s41746-020-00363-7](https://doi.org/10.1038/s41746-020-00363-7)
2. Vitality Tracker, What VT measures (catalogue of 15 October 2026).

## Related

- [Overnight resting heart rate](https://vitalitytracker.app/knowledge/overnight-resting-heart-rate)
- [Overnight blood oxygen](https://vitalitytracker.app/knowledge/overnight-blood-oxygen)
- [Overnight temperature deviation](https://vitalitytracker.app/knowledge/overnight-temperature-deviation)
- [Symptom Radar and Symptom Trend](https://vitalitytracker.app/knowledge/symptom-radar-and-symptom-trend)

Reviewed October 2026 · v1

Source: https://vitalitytracker.app/knowledge/overnight-respiratory-rate