Skip to main content
Sleep analysis — iOS
Mark avatar
Written by Mark
Updated over a week ago

Welltory Premium gives you a detailed sleep analysis that shows how well you slept last night — see what impacts your sleep, get tips to rest better, and keep tabs on 4 key sleep metrics.

Based on an in-depth analysis of your overnight heart rate patterns and historical sleep data, it’s personalized and packed with insights that will steer you toward better recovery.

If you’re a free user, check out a basic sleep assessment as a headline, see how your heart rate changed while you snoozed, and track your wake-ups.

How do I enable sleep tracking?

Wear your Apple Watch or any other fitness tracker that tracks your heart rate while you sleep and sends it to Apple Health.

If you have an Apple Watch

For Apple Watch Series 3 and above — enable sleep tracking either directly in Apple Health, or through the Sleep app on your watch. Just open Sleep and follow the prompts to set up your Sleep Schedule, then wear your Apple Watch while you sleep.

Alternatively, you can use a third-party Apple Watch app like AutoSleep, Sleep Cycle, or Pillow to track your sleep. Just make sure the data syncs with Apple Health, and you should be good to go.

For Apple Watch Series 1 and 2 — use a third-party Apple Watch app like AutoSleep, Sleep Cycle, or Pillow to track your sleep. Just make sure the data syncs with Apple Health, and you should be good to go.

If you have another fitness tracker

Make sure your tracker is synced with Apple Health — we’ll grab your sleep data from there and send the analysis to your feed.

How do I interpret my sleep analysis?

The message cover gives you a basic assessment of how well you slept last night, along with a chart that shows how your heart rate changed overnight and stats about your sleep.

Swipe left on the message to check out your Sleep score on the second page. It’s calculated based on 3 smart sleep metrics.

Tap on the details for a full breakdown of your sleep — you’ll see your raw sleep metrics, sleep insights, and full sleep analysis here.

The raw sleep metrics show the raw sleep data from your fitness tracker — your resting heart rate, wake-ups, and total sleep time are all here. This is the data our algorithms use to analyze your sleep.

Check out your sleep insights for an overview of how you slept and the optimal bedtime recommendations, and scroll down for a detailed breakdown of your smart sleep metrics. You’ll see which factors impacted your sleep quality most and learn more about what your body needs for better recovery.

What do my smart sleep metrics mean?

Your Sleep score takes into account 3 smart sleep metrics — Timing, Efficiency, and Recovery.


Timing takes into account how long you slept and how well you managed to stick to your usual sleep schedule.

For example, if you don’t sleep long enough, this metric will take a hit. Our algorithm also deducts points from your score if you go to bed way later than you usually do.

We use your historical sleep data to estimate how much sleep you need — some of us need the bare minimum of 7 hours, while others need a bit over 8 hours. A personalized approach is important, and our algorithm adapts to you over time.


Efficiency is a smart assessment of your sleep quality. It’s based on how much time it took you to fall asleep and how much time you spent awake throughout the night, then adjusted based on your overall sleep duration.

Falling asleep too quickly is a sign of exhaustion, but taking too long to fall asleep is also not a good sign — it could mean you’re too wound up and need a bit more downtime before you hit the hay.

Spending too much time lying in bed awake is also a sign of stress, and it takes a toll on your sleep quality.


We estimate your recovery by analyzing the overall pattern of your heart rate while you slept, as well as your resting heart rate toward the end of your sleep. The timing of your heart rate pattern’s low and high points say a ton about how well you’ve recovered, which is why we’ve learned to analyze them comprehensively.

IMPORTANT: For now, the Recovery metric doesn’t affect your Sleep score as much as the other two. This is an innovative metric — not just for our app, but for the science of sleep as a whole. It’s incredibly informative, but we’re working to fine-tune it as we gather more sleep data.

Is this all scientific?

Yes, absolutely — each metric is backed by research on the physiology of good sleep. We’ve read through hundreds of research papers to establish the norms for your Timing and Efficiency metrics, and learned to adapt them based on your historical sleep data.

For example, check out this 2018 University of Western Ontario study of over 10,000 participants, in which researchers found that sleep duration has a significant impact on high-level cognitive abilities such as problem solving. You can also read about the science behind the importance of sticking to a regular sleep schedule in this Washington Post article — it has pulled together all the research, explaining the findings clearly.

I don’t see a sleep assessment — just a graph that shows my overnight heart rate. Why?

There could be 2 reasons you’re not seeing our smart sleep analysis.

  1. Your data was incomplete, and we couldn’t use it to analyze your sleep reliably. Make sure your tracker is flat against your skin before you go to bed.

  2. Your tracker isn’t synced with Apple Health. Sync it, and we’ll grab your sleep data from Apple Health in order to analyze it. In the future, we’ll be able to analyze your sleep through direct integrations with Welltory as well.

Why don’t I see my Recovery score?

Occasionally, your sleep analysis may come without a Recovery score. There are 2 reasons this can happen.

  1. You slept for less than 6 hours. For now, it’s tough for us to assess your overnight heart rate pattern when you don’t sleep for long enough — there is just not enough data to make definitive conclusions about your physiological recovery.

  2. There wasn’t enough variation in your heart rate while you slept. Typically, there are clear dips and rises in heart rate while you snooze, which say a lot about your physiological recovery. When these variations aren’t clear enough in your data, we can’t make any definitive conclusions.

Why is my sleep analysis telling me to track my sleep more often?

Our full analysis takes your historical sleep data into account — how much you usually sleep, when you usually go to bed, and what your heart rate typically looks like while you sleep.

We can start analyzing your sleep as soon as you start wearing your tracker to bed, but your analysis will be more informative and actionable if you track your sleep regularly.

Did this answer your question?