How Somno Works?
Somno does not track and record users' sleep data directly. Instead, it connects to Apple HealthKit to obtain sleep data recorded and compiled by the Apple Watch. To experience a comprehensive data analysis, you need to wear your Apple Watch while sleeping.
The Apple Watch uses various sensors to detect physiological indicators during sleep, integrating this data and utilizing machine learning and sophisticated algorithms to infer and distinguish different sleep stages. While the data may not be as precise as laboratory EEG instruments, it still offers significant reference value for home use.
The physiological data monitored by Apple includes, but is not limited to:
The accelerometer in the Apple Watch detects body movements and changes in posture. By monitoring nighttime body activity levels, the device can distinguish between wakefulness, tossing and turning, light sleep, and deep sleep. For instance, body activity is typically low during deep sleep and higher during light sleep and wakefulness.
The Apple Watch continuously monitors heart rate using its built-in optical heart rate sensor. Different sleep stages are usually accompanied by distinct heart rate changes. For example, heart rate typically drops to its lowest during deep sleep and may fluctuate during REM sleep.
HRV refers to the variation in the time interval between heartbeats, which is an important measure of autonomic nervous system activity. HRV shows different patterns across sleep stages, being higher during deep sleep and lower during wakefulness and light sleep.
The Apple Watch can indirectly estimate users' respiration rates through heart rate and accelerometer data. Respiration rates vary across different sleep stages, providing additional data to help distinguish between these stages.
Some Apple Watch models (such as the Series 6 and later) include a feature for measuring blood oxygen saturation. While not a direct indicator for distinguishing sleep stages, blood oxygen saturation provides additional health information, contributing to a comprehensive assessment of sleep quality.
Is the Sleep Data from Somno Accurate?
Somno's sleep data is primarily sourced from Apple HealthKit, collected and compiled by the Apple Watch worn by users during sleep.
Somno visualizes this data and, based on literature from institutions such as the American Sleep Foundation, analyzes users' sleep patterns and offers improvement suggestions.
Both Apple Watch and other wearable devices measure heart rate using photoplethysmography (PPG) and combine various data indicators such as acceleration for comprehensive analysis and estimation. The accuracy of this data is approximately 80%. Although the final data may not be as precise as laboratory EEG instruments, it still holds considerable reference value for home use.
Can’t See Sleep Data or Incomplete Data?
If you can’t see your sleep data when you open the app, it might be due to the following reasons:
1. Apple Health Permissions Not Enabled
Somno does not actively track and record your sleep data (such apps typically require your phone to be unlocked and the app running in the foreground while you sleep). Somno’s sleep data is sourced from Apple Health. Somno requires authorization to access Apple Health. If the user denies reading permissions, Somno will be unable to provide data analysis services. To reauthorize:
- Open the Apple Health app on your iPhone.
- Tap on “Sharing” in the bottom navigation.
- Find and tap on “Apps” under “Data Sources & Access.”
- Scroll down, find, and tap on Somno.
- Tap the “Turn All Categories On” button at the to
Tips
We strongly recommend that users Turn On All requested permissions. Somno integrates various data points for comprehensive sleep analysis, and providing only sleep data will limit the depth of analysis results.
All user data will be stored locally and in encrypted iCloud, and we do not have access to users’ private data.
2.Data Sync Incomplete
When the sleep mode ends, the watch will update the data to Apple Health, at which point Somno will retrieve the sleep data from Apple Health and display it. Therefore, if you open Somno immediately after waking up, you might find the data hasn’t loaded yet. We recommend waiting a moment before checking or launching the app after receiving Somno’s daily report notification.
3. Sleep scheduling is not enabled
Please refer to the official guide below to enable sleep scheduling and Watch tracking.
Track your sleep on Apple Watch and use Sleep on iPhone
Why Can’t I See the Data for Deep Sleep and Light Sleep Stages?
If you cannot see detailed sleep stage data in Somno, first check if the Apple Health app contains stage data. If it doesn't, the reasons might be:
1.Not wearing Apple Watch during sleep
To get complete data for viewing and analysis, you need to wear your Apple Watch while sleeping. Otherwise, the Watch's sensors cannot capture multi-dimensional sleep data such as sleep stages, HRV, heart rate, and respiratory rate.
The sleep data provided by the iPhone alone only includes time in bed, which is detected through a relatively simple and less accurate mechanism.
2. Data synchronization not yet complete
If you wore your Apple Watch to sleep but only see time in bed data from your phone when opening the app, without sleep stage data, it might be because the Watch data hasn't fully loaded. Somno usually updates data after Sleep Mode ends. We recommend waiting for Somno's daily report notification before launching the app. Somno typically updates and pushes data promptly after Sleep Mode ends.
3. Apple Watch model or system requirements not met
This feature is only supported on iPhones with iOS 16
and above, and Apple Watches with watchOS 9
and above.
4. Sleep tracking not enabled on Apple Watch
Please open the Watch app on your iPhone, scroll up on the main page, find the Sleep option, and then turn on "Track Sleep with Apple Watch".
Set up your Sleep Schedule. For details, refer to Apple's official documentation:
Track your sleep on Apple Watch and use Sleep on iPhone
Why Is There No Data for Naps or Other Daytime Sleep?
On iOS 17 and earlier versions, Apple Health only records sleep during the set Sleep Schedule period and a short time before and after. It doesn't track daytime sleep, such as naps or afternoon rest. As a result, we're unable to access and display this data.
The latest iOS 18 and watchOS 11 now support daytime nap tracking. We'll be adapting and supporting this feature in future updates. Stay tuned!
Why Wasn’t My Sleep-In This Morning Tracked?
It might be because Sleep Mode ended when you turned off the alarm.
If you notice that your morning sleep data doesn't include some of your "sleep-in" time, it's likely because Sleep Mode ended and data collection stopped when you turned off the alarm. After the alarm is dismissed, Apple Watch no longer records subsequent sleep.
If you want your extra sleep time to be included in the statistics, we recommend choosing "Snooze" instead of turning off the alarm completely.
Why Is There No Sleep Data for the Weekend?
It's likely because you've only set up a Sleep Schedule for weekdays, but not for weekends.
We recommend enabling the Sleep Schedule for weekends as well, with bedtime and wake-up times that don't differ by more than 30 minutes from your weekday schedule. Maintaining a consistent sleep routine is a crucial factor in improving sleep quality!
For guidance on setting up your Sleep Schedule, please refer to the official Apple documentation.
Set up a Sleep Focus schedule in Health on iPhone
Why Is the Sleep Data Different from What’s Shown in Apple Health?
Somno currently only reads data from two sources: iPhone and Apple Watch, prioritizing Apple Watch data. Please note that data in Apple Health may also include information from other apps with write permissions, such as AutoSleep.
Additionally, Somno filters out very brief wake periods in its display for the following reasons:
- Very short wake times (micro-awakenings) are typically not noticed by users and don't affect the overall sleep experience.
- Sleep stages naturally alternate. Displaying very short wake periods would make the sleep stages appear overly fragmented. Incorporating these brief wake periods into core sleep or REM stages more accurately reflects the user's actual sleep experience.
What Is the Timing for Sleep Daily Reports, and Why Does It Seem That the Push Notifications Are Inconsistent?
Somno sends a sleep report notification as soon as Apple Health updates sleep data. This typically occurs when the user ends Sleep Mode. If the user doesn't use Apple Health's Sleep Schedule feature to manage Sleep Mode, but instead manages it manually with varying times, they may notice that Somno's sleep report notifications are sent at different times.