No Sleep Data

If you can't see your sleep data after opening the app, possible reasons include:

1. HealthKit Not Authorized

Tips

  1. Known iOS issue: In rare cases, updating iOS or Somno may reset Health permissions, preventing data from being read properly. If you notice anomalies in sleep data, please reauthorize in system settings.
  2. To ensure accurate sleep tracking and analysis, we recommend allowing all requested permissions. Somno analyzes multiple types of health data, and missing permissions may affect the experience.

Go to Somno Settings → Data Authorization to check and reauthorize permissions.

Or manually follow these steps:

  • Open the Health app on your iPhone
  • Tap "Sharing" at the bottom navigation
  • Scroll down and tap "Apps"
  • Find and tap "Somno"
  • Tap the "Turn All On" button at the top

2. Sleep Tracking Not Set on Apple Watch

Refer to the official guide below to enable sleep schedule and Watch tracking:

Track your sleep with Apple Watch and use Sleep on iPhone

3. Apple Watch Didn't Record Sleep

Common reasons include:

  • Improper fit: Wearing too tightly or too loosely may affect detection
  • Device communication issues: Bluetooth is off or Airplane Mode is on
  • Low battery or Low Power Mode:
    • If battery runs out during sleep, data may be incomplete or lost
    • Low Power Mode disables background heart rate and blood oxygen measurements, preventing detailed sleep stage data
  • Sleep tracking session was less than 4 hours

4. Apple Watch Data Not Yet Synced

Apple Watch syncs sleep data to Health only after sleep mode ends.

So if you open Somno during sleep mode or right after waking up, you might see a “No Data” message.

Additionally, low battery may delay syncing. Ensure your Apple Watch has enough battery at night for proper recording and syncing.

5. Third-Party Data Source Issue

If you're using a third-party sleep data source that only provides time in bed, make sure the corresponding setting is enabled in Somno:

Go to Somno Settings → Sleep Data Source → Turn on "Use time in bed as sleep data"

No Sleep Stage Data

If Somno doesn't show stages like Light, Deep, or REM sleep, first open the Health app to check whether stage data exists for that day.

If it’s also missing in Health, possible causes include:

1. Device or OS Doesn’t Meet Requirements

Only Apple Watch Series 4 and later, running watchOS 9 or higher, support sleep stage tracking (Light, Deep, REM).

Older models or OS versions won’t provide detailed sleep stage data in Health.

2. Third-Party Data Source Doesn’t Support

Some third-party apps (e.g., AutoSleep) don’t support writing sleep stage data to Health, so Somno cannot display it.

We recommend:

  • Selecting multiple data sources to improve coverage and completeness
  • Prioritizing apps that support sleep stage data in the settings

Sleep Data Not Updating Timely

If pulling to refresh still doesn’t show data, it's usually because Apple Watch hasn't synced with Health yet.

Follow these steps to manually check:

  • Open the Health app on iPhone
  • On the Summary page, tap Sleep
  • Scroll to the bottom and tap Show All Data
  • Check whether Apple Watch data has been written

If data hasn’t appeared, wait for automatic sync or check if your Watch is charged and connected properly.

Tips

It’s known that if you turn off the wake-up alarm in Sleep Schedule, syncing can be significantly delayed, and you may need to manually open the Health app for updates.

Not Receiving Sleep Reports

  • Background App Refresh is off
    Somno cannot send sleep reports in the background

  • Low Power Mode is on
    The system restricts background activity, causing delays

  • Apple Watch data sync delay
    Low battery or unstable connection may delay sync and report delivery

Sleep Report Data Differs from In-App Data

1. Data Source Priority

Somno reads from sleep data sources in priority order.

If a lower-priority source writes data first, it may trigger the sleep report earlier, while the app later updates to data from a higher-priority source, causing differences.

You can manage and reorder your sources in Somno Settings → Sleep Data Source.

2. Third-Party Data Issue

Some third-party sources may modify written data later, leading to discrepancies between the report and in-app data.

Missing Weekend Sleep Data

On iOS 18 + watchOS 11 and earlier, Apple Watch doesn't auto-detect sleep and relies on Sleep Schedule and Sleep Mode.

If weekend sleep is missing, it may be because only weekday schedules were set.

We recommend enabling a weekend schedule too, with wake and sleep times within 30 minutes of weekday times. A consistent sleep schedule improves sleep quality.

Refer to the official guide:

Set a sleep schedule in Health on iPhone

Naps Not Recorded

Using Apple Watch

On watchOS 10 and earlier, Apple Watch only records sleep during Sleep Mode. Once disabled, naps are not tracked.

Starting with watchOS 11, Apple Watch can auto-detect naps, but there are limitations:

  • Naps must last close to 1 hour or longer
  • Requires watchOS 11 / iOS 18 or later

Using Somno

Somno supports automatic sleep detection via Apple Watch, including short naps as brief as 15 minutes.

To enable this:

  • Install version 2.2.1 or later and open the Somno Watch app
    Ensure the app launches successfully on Apple Watch and completes initial sync

  • Grant necessary permissions
    Allow access to Health, Motion & Fitness, and Notifications on iPhone

  • Enable Background App Refresh
    Make sure Somno Watch has permission to refresh in background

Once all conditions are met, Apple Watch will automatically detect and record sleep while worn—no need to start manually.

See Somno Sleep Tracking Guide

Somno and Health Data Inconsistent

  • Data source and priority differences
    Data source priority in Health vs. Somno may vary, leading to discrepancies

  • Data source merging not enabled
    Health shows all combined data, while Somno disables merging by default to avoid data overlap

  • Short awakenings filtered in Somno
    Reasons include:

    1. Micro-awakenings are often unnoticed and don't impact sleep quality
    2. Sleep stages are naturally interleaved; removing brief awake periods makes the display more coherent. These are classified as core or REM sleep for better accuracy

  • Minute-level differences from data processing
    This is normal and expected

Support for Third-Party Devices

As long as your third-party device writes to HealthKit, Somno can read and display the sleep data.

Warning

Some third-party devices only record time in bed and do not store sleep stage data, which may limit Somno's ability to provide full analysis.

How to check if your device supports full sleep data:

  • Confirm if the device or app supports syncing with HealthKit
  • Open Health → Summary → Sleep → Show All Data to see whether sleep stage data has been written
Last Updated:
Contributors: Wendy Gao