Sleep is the foundation of our daily well-being and long-term health. But great sleep is not just about hours or stages — it’s about how well your body actually recovered. That’s why we’ve built Sleep Analysis: a smarter, science-based, and personalized way to see if your night truly restored your energy. It helps you improve sleep when needed, ease anxiety when everything is fine, and understand how rest fuels your overall wellness.
Please note that the new Sleep Analysis is currently available only to iOS users with an Apple Watch or an Oura. Android users can find more details in a separate article.
If you have any feedback or requests for new features about sleep, please share them with us through the Report a problem form. Also, you can use a feedback form in Sleep Report. For that:
Open Sleep Report
Scroll to the screen Dreaming of a better report?
Click the Share my thoughts button
Fill out the report
Click the Submit button
How we analyze sleep
Our complete Sleep Analysis is based on raw data from your Apple Watch or Oura device. Simply wear your gadget while you sleep to receive the detailed insights.
If you didn’t wear your Watch while sleeping but still see the sleep widget on the Today screen, you can manually add your sleep time. This way, you always get consistent results — including personalized bed and wake times.
Insight into your sleep last night
On the very first screen of your Sleep Analysis, you get the full story of your night at a glance. You’ll see your personal Heart Rate Wave — a unique visualization that shows whether your sleep was truly restorative — together with your Sleep Score, Sleep Time, and Heart Rate Range.
A short, personalized insight highlights exactly how well your body recovered, what went right, and what might have held you back. No digging through charts or numbers — just one clear picture that connects your night’s recovery to how you’ll feel today.
This makes Sleep Analysis more than just data. It’s a morning check-in that gives you confidence, lowers anxiety, and helps you start the day knowing where your energy really stands.
Sleep Data
To make it as convenient as possible for you to view all the key data your Apple Watch tracks overnight, we’ve compiled everything into a multifunctional chart. This chart displays your heart rate, activity, noise levels, respiration rate, SpO2, and sleep stages.
We hope this data helps you assess how accurately we’ve identified your sleep/wake times, as well as periods of wakefulness. If something doesn’t seem right, you can adjust the sleep boundaries by tapping Edit data in the pop-up window or using the pencil icon in the top right corner, because the more accurate the boundaries, the more useful and personalized your insights become.
Sleep Insights
This section summarizes your sleep over the weeks, months, and highlights last night. Everyone has ups and downs — the real value lies in recognizing the patterns: whether you’re getting enough rest overall, how consistent your wake times are, how often you wake up at night, and whether your body is recovering properly.
Sleep Score
Sleep Score provides an overall evaluation of your sleep quality. It is a comprehensive assessment based on four key parameters: Sleep Balance, Sleep Schedule, Sleep Stability, and Heart Rate Wave.
Think of it as your recovery score — one simple metric that explains whether your night actually recharged you. If the score is low, you’ll see exactly why: late bedtime, insufficient amount of sleep, frequent wake-ups, high nighttime heart rate, or all of the above.
Sleep Balance
Sleep Balance refers to the ratio between the time you slept (total time in bed, minus awake periods) and your sleep need (how much sleep your body requires to feel rested). Both oversleeping and insufficient sleep can be harmful, so maintaining a healthy balance is essential.
Sleep Schedule
This parameter assesses the consistency of your sleep routine. Ideally, you should go to bed and wake up around the same time every day. However, if you’re particularly tired and need more sleep, it’s best to go to bed earlier, but still wake up at your usual time.
A consistent Sleep Schedule helps your body regulate melatonin production, making it easier to fall asleep, stay asleep, and wake up refreshed. Consistency also promotes deeper, more restorative sleep by allowing your body to enter the sleep stages crucial for recovery, ultimately improving your overall health.
With Welltory, you don’t just see whether your schedule is consistent — you also get personalized Sleep and Rise Windows every evening. These windows adapt to your real life: if your schedule is irregular, the windows expand to fit; if your rhythm is stable, they reinforce it. Unlike rigid “go to bed at 10 PM” rules, Welltory gives flexible, guilt-free guidance tailored to your body’s actual recovery needs. You build a healthy sleep habit that fits your lifestyle — not the other way around.
Sleep Stability
Sleep Stability evaluates how restless your night was and whether your wake-ups interfered with recovery. Waking up briefly during sleep is normal, but multiple moderate (5–12 minutes) or long wake-ups (>12 minutes) can prevent your body from fully recharging.
Welltory makes these wake-ups transparent. Instead of just labeling your sleep as “restless,” we show you exactly how many times you woke up and how long each awakening lasted. That way, you can see the real reason behind morning fatigue — whether it was many short interruptions or a few long ones.
By monitoring Sleep Stability over time, you’ll see what helps reduce nighttime interruptions — from better evening habits to more consistent bedtimes. That gives you not just data, but a clear path to improving your recovery night by night.
Heart Rate Wave
Heart Rate Wave is Welltory’s signature feature — a way to see if your night was truly restorative. It reflects how your heart rate changed throughout the night compared to your personal baseline.
To calculate this, we need at least 30 nights of sleep data with your Apple Watch on. Your baseline is built from your best recovery nights and adapts over time as your patterns change.
Colored dots show actual heart rate values recorded during the night.
The smoothed Heart Rate Wave reveals the overall pattern.
Its color shows how your night compares to your baseline.
We evaluate your Heart Rate Wave based on three key factors:
Wave elevation relative to your baseline. If your heart rate remains higher than usual, it may indicate lower-quality sleep and less time in deep, restorative stages.
Wave shape. Ideally, your wave looks like a hammock: heart rate drops as melatonin peaks mid-night, then rises as cortisol prepares you to wake. If the shape is distorted, your sleep may not have been as restful as it could have been.
Heart rate before waking. If it’s lower than your baseline, your body might not have been ready to wake up; if it’s higher, it could signal incomplete recovery.
The shape of your Heart Rate Wave tells the true story of your night. Instead of vague averages, you see whether your body has really restored itself. Lifestyle factors, such as alcohol, stress, or late exercise, can appear immediately in your nightly wave.
Sleep Impact
This section helps you understand how your sleep from the previous night will affect your day. It provides insights into how much energy you’ll have, whether you’ve recovered from stress, and how well you’ll be able to handle the challenges of the new day.
In other words, Sleep Impact connects your night to your next day — turning sleep into a tool for planning, not just a record of the past.
Nighttime Recharge
This section shows how your body recharges during different sleep stages. Your Battery recharges more effectively when you get sufficient deep and REM (rapid eye movement) sleep each night.
Deep sleep repairs your body by restoring bones, muscles, and tissues.
REM sleep helps process emotions and maintains brain health.
Welltory builds sleep stages using its own algorithm based on two of the most reliable signals your body gives during the night: heart rate and movement. Low heart rate combined with stillness, for example, indicates deep sleep, while subtle changes in rhythm and activity reflect transitions between stages. By analyzing these dynamics, we create a stage model that is closer to what’s really happening in your body, rather than just relying on device defaults.
Nighttime Recharge also flows directly into your Battery indicator on Today Screen. Each morning, your Battery reflects how much energy you regained overnight, so you can start the day with a clear understanding of your real capacity — not just how many hours you slept.
Morning Stress Level
Your sleep determines how easily you will handle the challenges of the new day.
If you haven’t had sufficient sleep, it can create stress in your body’s regulatory systems, forcing your body to use more energy to function and reducing your resilience to daily stressors. However, if you’ve slept well, it helps release the stress from the previous day and recharge your stress resilience for the day ahead.
Morning Stress Level is directly reflected in your Stress widget on Today screen. Instead of guessing how stressed your body is, you wake up with a clear, data-driven view of your resilience. If your morning stress is high, you’ll know that poor sleep is part of the reason. If it’s low, you’ll see how well your night restored balance.
This makes stress something you can track and manage, not just feel — helping you connect nighttime rest with daytime performance.
Sleep Need Forecast
This feature illustrates how your need for sleep accumulates throughout the day. It’s influenced by how well you slept the previous night, your usual sleep patterns, and your daily activity, stress levels, and rest. On highly active or stressful days, your need for sleep will increase compared to your usual levels. On more relaxed days, it may decrease.
Sleep Guidance
This section appears in the evening, once we’ve calculated your optimal bedtime and wake up time.
Sleep and Rise Windows
The recommendations for your Sleep and Rise Windows vary from day to day based on your daily routine and accumulated sleep need, while still considering your usual schedule. If your schedule is inconsistent, your Sleep and Rise Windows will be wider to account for the variability.
What makes this feature unique is its flexibility. If your routine is inconsistent, your windows expand to give you more room — no pressure, no guilt. If your rhythm is stable, your windows narrow to reinforce healthy consistency. Unlike rigid “go to bed at 10 PM” rules, Welltory adapts to your real life and personal recovery needs.
Each evening, you get a simple, personalized window of when it’s best for you to fall asleep and wake up. Following it helps your body regulate melatonin for sleep and cortisol for waking, so you drift off more easily, stay asleep throughout the night, and wake up refreshed.
Sleep Lake
When you log your sleep manually via Apple Health or Oura, we compare your total sleep time with both your sleep needs and your typical schedule. That’s what forms your Sleep Lake. For deeper insights, try wearing your Apple Watch or Oura while you sleep.
If you slept with your device but see Sleep Lake, open your app (Apple Health or Oura) and make sure the data is synced.
FAQ
Some data are not displayed in the sleep data chart. What should I do?
1. Heart rate is not displayed
If you slept with your watch on, but your heart rate wasn’t recorded, your watch may have been in power-saving mode, which either disables heart rate tracking or records it infrequently.
If your heart rate data is available in Apple Health but not displayed in Welltory, please send us a bug report by going to Menu → Report a problem, describe the issue, and we’ll investigate what went wrong.
2. Tossing & turning is not displayed
This indicator is calculated based on Active Energy data from Apple Health. Please ensure that you’ve granted Welltory access to this data by going to Apple Health → Profile → Apps and Services → Welltory → and enabling Allow Welltory to read.
If this data isn’t recorded for several days in a row despite permissions being granted, please send us a bug report through Menu → Report a problem, describe the issue, and we’ll investigate what went wrong.
3. Noise (Environmental Sound Levels) is not displayed
This feature is available for Series 4 Apple Watch and above, running iOS 13 and watchOS 6+.
First, ensure that noise data is being recorded. Open your Watch app on your phone, scroll to Noise, and turn it on.
If it’s already enabled, confirm that Welltory has permission to access Environmental Sound Levels by going to Apple Health → Profile → Apps and Services → Welltory → and enabling Allow Welltory to read.
If this data isn’t recorded for several days despite permissions being granted, please send us a bug report through Menu → Report a problem, describe the issue, and we’ll investigate what went wrong.
4. Respiratory Rate is not displayed
This feature is available for Series 3 Apple Watch and above, with iOS 15+ and watchOS 8+.
To ensure Respiratory Rate is recorded, make sure the Track Sleep with Watch setting is enabled. Open the Watch app on your phone, scroll to Sleep, and enable Track Sleep with Watch.
Additionally, check the Privacy section in your Watch app to confirm that this stream is enabled.
If it’s already on, ensure that Welltory has permission to access Respiratory Rate by going to Apple Health → Profile → Apps and Services → Welltory → and enabling Allow Welltory to read.
Lastly, Respiratory Rate will only be recorded if Sleep Mode is enabled on your watch. This mode turns on automatically if you have a sleep schedule set up on your phone. If not, you can enable it manually by tapping the bed icon on your watch.
5. SPO2 (Blood Oxygen) is not displayed
This feature is available for Series 6 Apple Watch and above.
To ensure Blood Oxygen data is recorded, make sure the Track Sleep with Watch setting is enabled. Open the Watch app on your phone, scroll to Sleep, and enable Track Sleep with Watch.
Additionally, check the following settings in the Watch app:
In the Privacy section, confirm that the Blood Oxygen stream is enabled.
In the Blood Oxygen section, ensure all toggles are turned on.
6. Sleep stages are not displayed
To display sleep stages, you need to wear your watch while sleeping.
Additionally, ensure that Welltory has access to both Heart Rate and Active Energy data in Apple Health by going to Apple Health → Profile → Apps and Services → Welltory → and enabling Allow Welltory to read for these data streams.
Why do sleep stages in Welltory differ from Apple Health or other sleep trackers?
Because Welltory doesn’t just copy device defaults. We calculate the duration and timing of each stage using our proprietary algorithm, which is built on two physiological signals during sleep: heart rate and movement. This approach provides a stage model that’s closer to what’s actually happening in your body.
Can I use Apple's sleep stages instead of yours?
Yes, to use Apple sleep stages in your calculations, go to Menu → Settings and turn on Use Apple Sleep Stages.
Why do my sleep duration and time calculations update after I wake up and view my analysis?
Sometimes the Apple Watch requires additional time to sync with Apple Health, which is where we access the data used in our analysis. As a result, we rely on the data that has been synced and update your analysis once we receive more refined data from Apple Health.
Why add sleep and wake times if I didn't sleep with my watch on?
Sleep and wake up times, along with total sleep duration, are key indicators for evaluating your sleep routine and providing the most accurate Sleep Guidance. The more accurately we understand your sleep patterns, the better our recommendations and analysis will be for the nights when you do sleep with your watch on.
Also, knowing your sleep time allows us to calculate your energy levels, which are displayed in the Battery section.
Why don't I receive sleep messages in my feed anymore?
If you’re receiving the new sleep analysis on Today screen, you will no longer receive sleep messages in your feed. We’re moving the most important sleep information to a more accessible place.
Additionally, we’re currently working on developing Journal, where soon a sleep message based on the new analysis will be saved.
How can I view sleep data for previous days?
You can view the previous day’s scores and main parameters in Sleep Report under the Days tab. While the raw data graph and pulse wave are not yet available for the previous days, we’ll add this feature soon.
How do I correct sleep time?
To adjust the start or end time of your sleep, use the Edit button in the pop-up window within the sleep analysis, or click on the pencil icon in the top right corner of the sleep analysis screen.
Please note that, for now, you can only correct the sleep data from the current day.
Why don't I see new Sleep Analysis?
New Sleep Analysis is currently only available to iOS users with an Apple Watch or Oura.