Reading sleep data the right way.

Sleep stages are estimates

A watch on your wrist cannot see whether you are asleep. It analyses movement and other sensor data. That is why Apple’s Health app explicitly refers to the estimated time you spent awake, in REM, core or deep sleep.

For everyday use this means: when the night began and ended is usually easy to read. The split into stages is an approximation and can differ from your own impression.

Every manufacturer names the stages differently

Apple shows the stages Awake, REM, Core and Deep. Health Connect on Android includes the stages awake, awake in bed, out of bed, light, deep and REM. Other manufacturers use their own names.

“Core sleep” on Apple and “light sleep” from another provider are therefore not automatically the same. After switching watches, the distribution of stages can look different even if the nights were similar.

A sleep score combines several values into one number

Some apps condense the night into a score. The sleep score in Apple’s Health app ranges from 0 to 100. It is made up of sleep duration (50 points), bedtime consistency (30 points) and interruptions (20 points).

A number like this is handy for a quick look. But it does not show which part pulled a night up or down. In your history, sleep duration itself is easier to read.

Gaps usually come from the measurement

Apple names two requirements for sleep tracking: wear the watch for at least one hour per night and charge it to at least 30 percent before bed. If the band is too loose, Apple says the accelerometer may register too much movement.

A missing or unusually short night in the chart is therefore first a question of measurement. In mypacing, days without a value stay a gap in your history. The line does not connect them.

mypacing compares sleep duration with your usual range

In the daily picture, sleep is one of three values, alongside resting heart rate and HRV. mypacing compares sleep duration with your usual range over the last four weeks and describes the result in one sentence, such as: “You slept longer than usual.” In the check-in you also note how your sleep felt: restless, so-so or restful.

Seeing both side by side shows whether the measured duration and your own feeling match. mypacing does not judge this. It is a description for your review.

Sources

All information on this page is based on legal texts, public authorities and manufacturers’ documentation. Most sources are in German. The description of mypacing features reflects the app as of 20 October 2026.

• Deinen Schlaf auf der Apple Watch aufzeichnen und „Schlaf“ auf dem iPhone verwenden, Apple Support. Accessed 20 October 2026.
• Schlafprotokoll in der App „Health“ auf dem iPhone anzeigen, Apple Support. Accessed 20 October 2026.
• Track sleep sessions (Health Connect), Android Developers. Accessed 20 October 2026.

Read more