How Apple Health Tracks Respiratory Rate in iOS 15

In iOS 15 and watchOS 8, Apple introduced sleeping respiratory rate tracking to help users gain deeper insights into their nightly wellness and overall health. By pairing an iPhone with an Apple Watch, the Health app automatically measures and logs your breaths per minute while you sleep, establishing a personal baseline and highlighting meaningful trends over time.

The Technology Behind the Measurement

The Health app does not measure airflow directly; instead, it relies on the built-in accelerometer inside your Apple Watch. When you sleep, the chest and torso subtly rise and fall with each breath. The accelerometer detects these micro-movements across your sleep session.

Using dedicated algorithms, the device processes these motion signals to compute your average breaths per minute (brpm) throughout the night.

Requirements for Tracking

To evaluate respiratory rate, the system requires the following:

  • An iPhone running iOS 15 or later.
  • An Apple Watch (Series 3 or later) running watchOS 8 or later.
  • Track Sleep with Apple Watch enabled in the Apple Watch app.
  • Sleep Focus active during bedtime to ensure sleep stages and movement are properly isolated from wakeful periods.
  • Wearing the watch snugly to sleep for a sustained session (typically at least four hours).

How the Data Is Evaluated

Once recorded, the data syncs to the Health app on your iPhone. The evaluation process involves:

  • Establishing a Baseline: A typical resting respiratory rate for healthy adults ranges between 12 and 20 breaths per minute. Apple Health analyzes several nights of data to calculate your personal normal range.
  • Trend Analysis: Because sleeping respiratory rate remains relatively consistent night after night, deviations can serve as early indicators of physiological changes. The Health app flags notable increases or decreases, allowing users to spot patterns linked to illness, alcohol consumption, high altitude, or sleep environment changes.
  • Integration with Other Metrics: Respiratory rate is evaluated alongside other sleep metrics—such as resting heart rate, blood oxygen (SpO2), and total sleep duration—providing a comprehensive view of sleep quality.

Viewing Respiratory Rate Data in iOS 15

To review your recorded respiratory rate:

  1. Open the Health app on your iPhone.
  2. Tap the Browse tab in the bottom right corner.
  3. Select Respiratory, then tap Respiratory Rate.
  4. Use the tabs at the top (D, W, M, 6M, Y) to view daily averages, ranges, and long-term trends.