Sleep & recovery
How to see your sleep stages on iPhone
Your iPhone can show how a night was split into deep, core and REM sleep, but only if something writes those stages to Apple Health. An Apple Watch does it once sleep tracking is on. Many other watches and rings send only the time you fell asleep and woke up, so the Health app shows one grey block instead of a night. Here is where to find your stages, which devices supply them, and how to fill the gap when yours doesn’t.
Short answer
Open the Health app, tap Browse, then Sleep, and tap Show More Sleep Data. The Stages view shows Awake, REM, Core and Deep sleep per night. With an Apple Watch, turn on Track Sleep with Apple Watch in your Sleep Focus settings and wear it to bed. If your stages come from another watch that doesn’t write them to Apple Health, you need an app that reads that watch’s account and writes the stages for it.
Find your sleep stages in the Health app
- Open Health on your iPhone and tap Browse.
- Tap Sleep. The chart shows time asleep for the last nights.
- Tap Show More Sleep Data and choose Stages to see Awake, REM, Core and Deep sleep, night by night, with the time in each.
- Switch between day, week and month to see averages. Tap a single night for its timeline.
If the Stages view is empty but you see a time asleep, your data source writes sleep duration only. The Health app can’t work stages out on its own.
Turn on sleep tracking on Apple Watch
Apple Watch records stages when sleep tracking is on. In the Health app, go to Browse ▸ Sleep, set up a sleep schedule if you haven’t, and make sure Track Sleep with Apple Watch is on under Options. Wear the watch to bed with at least about 30 % battery. Recent watches also show a sleep score for the night on the watch itself.
Which devices write stages to Apple Health
| Source | Sleep stages in Apple Health |
|---|---|
| Apple Watch with Track Sleep on | Yes |
| Polar Flow’s own Apple Health sync | Sleep times only |
| Garmin Connect’s own Apple Health sharing | Sleep times only |
| Polar or Garmin through Keho’s sync | Yes |
Polar Flow sends a night as one block with a start and end time; its stages stay in Polar Flow. Garmin’s Apple Health sharing likewise covers sleep times rather than the stages Garmin Connect shows you. Other apps and rings vary, so check the Stages view after a night or two.
Get stages from a watch that doesn’t send them
Keho’s syncs read your watch’s account and write what its own Apple Health connection leaves out. Keho Polar Sync writes sleep stages, 24/7 heart rate, breathing rate, SpO2 and temperature. Keho Garmin Sync writes your activities, sleep stages and all-day heart rate. Each sample carries a stable identifier, so syncing again never creates duplicates, and data written by Polar Flow or Garmin Connect itself is never touched. Once the stages are in Apple Health, every app that reads sleep sees them, the Health app included.
How to read your stages
Single nights vary a lot, so read stages as a trend over a week or two. A few rules of thumb from sleep research for adults:
- Deep sleep comes mostly in the first half of the night. A late, heavy meal, alcohol or a hard evening session often cut it short.
- REM sleep builds towards morning, so a short night costs REM first.
- Core sleep (Apple’s name for light sleep) usually makes up about half the night.
- Awake moments are normal. Most of them you never remember.
Wrist and ring sensors estimate stages from movement and heart rate; they are good at trends and less exact than a sleep lab for any single night. Total sleep and how regularly you go to bed often say more than the split. In Keho, the Sleep tab shows each night’s stages beside your sleep debt and bedtime regularity, so one night never tells the whole story.
Common questions
Why does the Health app show my sleep but no stages?
Your data source writes sleep duration only. Turn on Track Sleep with Apple Watch, or use an app that writes stages from your watch’s account.
Can I see naps in Apple Health?
Apple Health shows them as extra sleep entries when a device records them. Keho shows naps beside your night on the Sleep page, from your Apple Watch or found in Polar’s 24/7 data, and lets them ease your sleep debt.
Is my sleep data sent anywhere?
The Health app keeps it on your devices. Keho reads and writes it on your iPhone, with no Keho account.