Best Sleep Trackers 2021: Whoop Band vs Apple Watch vs Oura Ring

Best Sleep Trackers: Whoop Band vs. Apple Watch vs. Oura Ring

What They Do & How To Use Them.

We are in the midst of a digital health revolution. As technology in almost every department ie. transportation, computer capabilities, communication, space travel, etc. are experiencing exponential growth with every passing year, we are also seeing a boom in innovative wearable technology that are relatively inexpensive and yet highly sophisticated in tracking an array of bio-signals such as our heart rate and its variability, our bodies temperature, our physical activity, and how all these factors behave during and contribute to our sleep. 

While we are seeing leaps and bounds in advancements of these wearable tech devices, there’s a lack of information and user guidance beyond the marketing tactics of these companies. As consumers, it is not easy to find objective information explaining how this tech actually works and the science behind its use. That’s why we’ve taken it upon ourselves to deep dive into the topic. We want to pull back the curtains and shed some light on the information these wearable sleep trackers are gathering and how you can use them to troubleshoot sleep issues and optimize your sleep and recovery.

We have chosen to focus on the following three wearable sleep trackers: 

Whoop vs Apple Watch vs. Oura

We want to assure you that this is not some surface level consumer review. It is an intense analysis of each of these sleep tracker products, after months of using the devices and correlating the user experience with accredited sleep science. If you do not yet have a sleep tracker and are looking to get one, this article will help you understand your options and how to best use each one. People who already have a Whoop, Apple Watch, Oura can also benefit from better understanding the devices, the metrics they track, why they get the numbers they get when using them, and ultimately, what to do with that information. 

The science behind sleep tells us that during sleep, every one of our body systems - skin, metabolism, digestion, heart, lungs, immune system, sex organs and reproduction, hormones, the brain - are repairing and recovering, allowing us to be fit and ready to tackle another day. When people experience consistent sleep deprivation, every one of these systems suffers.  

This is why our priority in using sleep trackers is to gain deeper insights into our sleep quality and recovery so that we can start making the right adjustments to encourage optimal sleep. 

When choosing a sleep tracking device, we want something that reports on the following metrics:
  1. Total sleep time and start/end time of sleep
  2. Sleep latency (how long it takes to fall asleep)
  3. Sleep Efficiency (time in bed vs time asleep)
  4. Time in REM sleep
  5. Time in Deep sleep 
  6. Resting Heart Rate (RHR)
  7. Heart Rate Variability (HRV)
  8. Respiratory (breathing) Rate
  9. Body Temperature
  10.  Activity tracking (day strain) 
  11. Journal options

What these metrics are and why we care about them:

 1. Total sleep time and start/end time of sleep. 

These are the most basic indications of your sleep hygiene. They tell you whether you’re keeping a consistent sleep schedule. You can also start to draw patterns around your ideal amount of sleep. For most people, ‘ideal’ is somewhere between 7 and 9 hours per night. 

It also matters when those sleeping hours occur. People find they feel most rested when those hours are on a consistent schedule and at a time that jives with their biology. For early birds, the ideal timing might be 9pm to 5am. For some people, it’s 11pm to 6am. For others, it’s 12am to 8am.. You get the idea. We’re all different in terms of when we do our best work, best workouts, and best sleep. 

Step one for optimizing sleep and recovery is knowing when and how long your best sleep happens. 

2. Sleep Latency.

Sleep latency means how long it takes for you to fall asleep. A ‘normal’ sleep latency is between 5 and 15 minutes. Shorter typically means you’re really tired when you are getting into bed, so you either haven’t been sleeping enough, or you’re going to bed too late. Longer than 15 minutes is an indication that you need some help winding down. It could be that you did something that got your system amped up too late in the day (late caffeine, late workout, late meal), that your system is stressed out, or that your body clock isn’t initiating sleep when you want it to. 

3. Sleep Efficiency.

Sleep efficiency means the time you spend in bed vs. the time spent asleep. It is normal to have some minor sleep disruptions in the night and to spend a few minutes awake. Normally, your sleep efficiency should be greater than 80%. If you are constantly waking up in the middle of the night and spending a higher percentage of time awake in bed, you’re not getting enough good quality, restorative sleep. This can mean that you need to make some changes in your sleep environment (sound, lighting, temperature, bed partner, etc) or that your stress levels are high and you’re waking up from elevated cortisol and adrenaline at night. Night waking tends to increase with age and is strongly related to hormone changes like menopause. It is also related to trouble with blood sugar regulation. 

You can also correlate your sleep efficiency with your resting heart rate and heart rate variability stats. If your HR is high and your HRV is low, your sleep disruptions are likely stress related.  

4. Time in REM Sleep - Most crucial for mental recovery. 

REM sleep - aka dreaming sleep - is a time when your brain is consolidating memories and building neural pathways. It is associated with learning, memory, and positive mood.

In adults, REM sleep should make up 20-25% of your total sleep time. If your sleep tracking device also shows when you get those hours - even better. You should see that you spend less time in REM phases early in the night and have longer REM cycles towards the end of the night (early morning). 

If your REM sleep is less than it should be, you might be waking up earlier than your body wants to and cutting off your longest and most significant REM cycles. 

REM sleep tends to decline with age. Young children can spend up to 50% of their sleeping hours in REM sleep, which is vital for the growth and development of their brains. 

5. Time in Deep Sleep - Most crucial for physical recovery. 

During deep sleep, your body releases growth hormone which contributes to the growth and repair of your cells. It is critical for muscle healing and growth after a workout, as well as keeping your skin, joints, and organs healthy. Getting enough deep sleep improves your energy production and metabolism, lowers blood pressure and improves cardiovascular health, and boosts immune function. Adults should spend between 1.5 to 2 hours or between 10% and 20% of their total sleep time in deep sleep (also known as N3/stage 3/slow wave sleep). Most of your deep sleep should happen early in the night, with your longest cycles of deep sleep happening in your first few hours. 

Deep sleep is easily disrupted by alcohol, stress, medications, and by late exercise and meals. Like REM sleep, the amount of deep sleep that we get tends to decline with age.

6. Resting Heart Rate (RHR)

In general, a lower resting heart rate is an indication of good health and recovery. Your RHR each night can change based on hydration levels, timing and intensity of physical activity, body temperature, stress levels, alcohol ingestion, pharmaceuticals and other drug use, and meal size and timing. 

In general, the lower your average RHR reaches during a night of sleep, the better your recovery is likely to be. Lower average RHR also tends to correlate with high average HRV.

7. Heart Rate Variability (HRV).

Heart rate variability is the difference in timing between your heart beats. It is measured in milliseconds (ms).  

Your heart does not beat at a perfectly constant rate. Your nervous system controls the speed of your heart rate. In general, your nervous system has two branches. You have a stress response “fight or flight” branch, called the sympathetic nervous system. You also have your “rest and digest” branch, called the parasympathetic nervous system. Each branch is constantly communicating with your heart. The stress side tells the heart to beat faster and the rest side tells it to slow down. When these inputs are in balance, there is a significant difference in the timing from one heart beat to the next, HRV is high.  

A greater variance in the timing between beats is a sign that your body is highly adaptive and attuned to responding to the environment. Higher HRV is a sign of good recovery and high readiness to tackle challenges.  

If you have low heart rate variability it is a sign that one side of your nervous system is dominating the other. For example, when you are exercising, your stress system is dominating and causing an increase in heart rate. This is what is supposed to happen. However, when you are at rest, your heart rate should recover and the two sides should come back into balance, bringing your HRV back up. 

Low HRV while you are sleeping indicates that your body is working hard on something - your body could be stressed, injured, sick, dehydrated, or fatigued from over exertion. 

There is not one ideal range for HRV. Age, gender, genetics, and fitness level all contribute to give each person their own ‘normal’ range. Some people will find that their ‘healthy’ normal HRV is around 40 ms while for others that number might be 120ms or higher. 

With HRV, the insights you gain are from comparing yourself to yourself. What is your HRV on a great day, compared to a normal day, compared to a rough day? Over time, when you track your HRV you will come to understand what is a good HRV level for you and what HRV indicates that your body is struggling to recover and get out of its stress zone. 

A good sleep tracker will automatically factor in your accumulated HRV data over time and give you feedback relative to trends in your HRV. 

8. Respiratory (breathing) Rate.

Respiratory (breathing) rate is the number of breaths you take per minute. It is a general reflection of your cardiovascular health. Normal range for healthy adults is about 14-18 beats per minute.

Unlike HRV and RHR, you rarely see a large difference from night to night in your respiratory rate. It’s nearly always within about 1 breath per minute of your normal rate. However, seeing a significant change in your overnight breathing rate can be an early sign of something being off - such as an illness or other highly stressful event affecting your system. 

9. Body Temperature.

Similar to respiratory rate, it is unusual to see large swings in body temperature from night to night. However, body temperature is another good metric to keep on your radar for indications of infection or other major changes in your system. Any fluctuation greater than 0.5°C / 0.90 °F is something that should raise some flags in your mind. 

10. Activity Tracking (day strain) 

Correlating your activity data and sleep data is an important way to observe trends and make changes to improve your sleep and recovery. It also helps to know when your body is primed to push yourself hard, optimizing your performance and avoiding overtraining. 

11. Journal options

Keeping a sleep journal is a great way to understand your sleeping patterns as they correlate with your external lifestyle factors so that you’re able to identify what may contribute to poor sleep quality and recovery. Your journal can be as simple as making a note that you had a coffee late in the day or that you worked out, or as detailed as you’d like, as long as there’s enough information in there to track the lifestyle habits that may not be serving your best sleeps. 

User Experience (UX) :

The apps, algorithms, and scores (sleep quality and readiness).

For any sleep tracker, the accompanying software is where you get all of the reporting on the metrics it is tracking as well as insights and information on how you can derive meaning from the data. Each device has its own proprietary algorithm to assess your different bio-signals, metrics, estimate time spent in different sleep stages, and give you insights on how to modify your behaviour in order to improve your sleep

The user experience is very different for each of the Apple Watch, Whoop, and Oura Ring, and it makes a huge difference for what you get out of using each device. 


The Whoop Device

The Whoop strap is a band that you wear either on your wrist or upper arm. The straps are adjustable and come in a wide variety of colors and styles. The device is waterproof. The band comes with a battery pack that you plug into the wall. The battery pack slides onto the band to recharge the Whoop without having to take it off. 

Whoop UX

The Whoop app is straightforward and easy to use and it has a good introductory walk through to orient you to syncing your device and navigating through the reports and features. 

There are 4 main screens to swipe through which give you an overview of your previous night sleep, your current day strain, your recovery score, and your sleep performance. You can also scroll down on each screen to access additional charts and data from the previous week. There are little insight boxes that correlate your journal entries (more about that below) and make recommendations based on your recovery score and day strain. If this sounds confusing to you, that’s because at first, it is. It took us a while to remember where to access different bits of information and we spent a lot of time scrolling around when we first got our Whoop strap. 

Whoop Sleep Score

The Whoop sleep score is called a ‘Recovery Score’ and is reported as a number out of 100. 

Each morning it ‘processes’ your sleep after you wake up and provides you with a read out of your total sleep time, time in bed, number of sleep interruptions, and time spent in each sleep stage: Light, REM, and Deep Sleep.

The Recovery Score is based on 4 metrics: 

  • Resting heart rate (RHR)
  • Heart rate variability (HRV)
  • Respiratory rate
  • Sleep time

In general, higher HRV and lower RHR result in a better Recovery Score. The longer and more consistently you wear your Whoop, the more accurate your score should become since "high" and "low" HRV and RHR are relative to you and your baseline - which it keeps as a running 30 day average.

It is also important to note that the HRV and RHR scores used to calculate your Recovery Score are both captured during the last episode of your slow wave sleep each night. They are not based on the whole night. 

Whoop Sleep Stages

The Whoop tells you how much time you spend in deep sleep, REM sleep, and light sleep. We have not been able to find information telling us how they decide which stage of sleep you are in. We assume this is kept private to protect their intellectual property and patents. However, there has been a third party study comparing the sleep data obtained from the Whoop to conventional sleep studies (using electrodes attached to the brain while you sleep in a lab). The Whoop data was fairly consistent with conventional sleep studies, though less accurate - which is to be expected. 

Related: A Validation Study of the WHOOP Strap Against Polysomnography to Assess Sleep

Whoop Readiness Score

The Whoop uses the recovery score to recommend a target range for your day strain. The worse your recovery, the less strain it recommends. We’ll expand on this more below in our discussion of the Activity Tracker.  

Whoop Activity Tracker

The Whoop tracks your heart rate and activity levels and keeps a running report of your day strain.  

According to their website, Whoop’s Day Strain is measured on a 0 to 21 scale, which is based on the Borg Scale of Perceived Exertion.  It is primarily based on your heart rate. The more time you spend with an elevated HR, the higher your day strain will be. The scale is not linear, meaning the higher it goes, the harder you must push your body to get a higher score. 

One complaint we have about the Day Strain is that it does not accurately reflect the stress you put on your body when lifting weights or working on skills. Skill work and weight lifting can be challenging to your muscles and your nervous system, without significantly increasing your heart rate. So the strain is really only a reflection of cardiovascular challenge.  

The Activity Tracker in Whoop automatically detects workouts (most of the time) and lets you categorize the type of activity. It will tell you how much time you spent in certain ranges of your max heart rate and compare it to other similar workouts. 

There is also a live feature where you can see your HR in real time and video record your workouts. When connected to your phone, it will also GPS track your runs/bike rides, etc. 

You can manually enter your workout if it does not pick it up automatically. 

Another unique feature in the Whoop app is the Community Tab. Here you can join groups and create your own friend groups where you can view the recovery and day strain of other Whoop users and see how you compare.  

The most important feature that we like about the Activity Tracker is that it correlates the data with your sleep and recovery so that you can plan your training and have an idea of when to push it hard and when to dial it back in order to optimize recovery and performance. 

Whoop Journal

Of the three devices, the Whoop journaling feature is the easiest to use and most relevant. Before calculating your sleep score, it prompts you with a series of yes/no questions which you can tailor to be most relevant to you. For example, we have ours set to ask questions about alcohol use, late meals, supplements, and reading in bed. It is really quick to swipe through them and you can add additional information if you want to - like the number of alcoholic beverages you had and how late your last caffeinated drink was. It gives you insights like “Your HRV typically increases by 4.0% when you report Reading in Bed. In the 38 times you’ve reported this behaviour, your average Recovery has been 64%”

This is a feature that we LOVE because it helps us to see the real impacts of our daily activities on our sleep and recovery. 

Whoop also provides weekly and monthly reports correlating your journal data, activity data and sleep data so that you can see the trends and make changes to improve your sleep and recovery. 

Whoop Cost

Unlike the Apple Watch and Oura Ring, the Whoop works based on a subscription model. It costs about $30 USD per month (though slightly cheaper with longer subscriptions) and they send you one strap and battery pack when you sign up. You can purchase additional bands (starting at $39 USD), battery packs ($30 USD) and accessories on the website. 

Our Whoop Experience

If you’re looking for a device to use both for activity tracking and sleep tracking, this is the best option of the three. It has clearly been designed for athletes and active people who are trying to optimize their fitness and recovery. The insights are presented in an easy to digest format and are helpful for informing your fitness pursuits and sleep. While the sleep stage reporting (REM and deep sleep) might not be 100% accurate (we find they consistently differ from what our Oura ring reports) the consistency within the app means you can still derive a lot of meaning from comparing yourself to yourself from night to night.

In general, we find that the Recovery score is reflective of how we feel – lower score days tend to match feeling less energetic. However, we occasionally get outlier scores – really high like 98 or really low like 12 – which are less reflective of how we feel. Scores can also fluctuate massively from one day to the next. You can wake up a 20 one day and be a 96 the next, which is almost never in line how our body feels and makes it a little bit harder to follow trends related to our training volume. This is likely because it compares you to your 30 day average, so if you’ve had a number of higher stress, lower recovery days in a row and then have a lower stress day where your HRV and RHR bounce back well, your relative recovery is huge – even if you don’t feel like you’re a 96.

With the lower upfront cost and all of the detailed metrics and insights that it provides, we think the Whoop is great value for a very useful tool.

Apple Watch

The Apple Watch Device

The Apple Watch is comfortable and it looks great. There are lots of options for watch and band designs. The apple watch is also waterproof. The battery only lasts about 24 hours, which makes this less ideal as a sleep tracker since you need to take it off to charge it.

Apple Watch UX

The Apple watch does not really have its own sleep app data and algorithm. The ‘stock’ feature that comes preloaded in your phone is Apple’s ‘Health’ app. Here you can get basic reporting on your sleep time, time in bed, an average daily HRV and HR, but to get real insights or feedback on sleep quality, REM and deep sleep, you need to find a third party application. There are a number of different options, some of which are recommended in the Health app. We downloaded the most popular one: ‘AutoSleep Track Sleep on Watch’ by a developer Tantissa.   

Apple Watch Sleep score

The ‘AutoSleep Track Sleep on Watch’ app gives a sleep quality score based on your HR, restlessness, and total time asleep.

Apple Watch Sleep Stages

There is no sleep stage information in the Apple Health app. 

The AutoSleep app gives an amount of deep sleep, estimated based on lowering of your HR and muscle movements. No REM sleep or light sleep data is available. 

Other app options might have better insights for sleep stages. 

Apple Watch Readiness Score

There is no readiness information in the Apple Health app. 

The AutoSleep app gives a readiness score, rated out of 5 stars, that is based on your waking HRV and HR.

Apple Watch Activity Tracker 

The Apple Health app automatically keeps track of steps, walking and running distance, calorie burn, time standing, workout minutes, cardio fitness, and mindfulness minutes. There are other activity and workout tracking apps that you can download to get additional tracking and GPS integration for running, etc.  

The information from the activity tracking does not correlate at all with your sleep data.

Apple Watch Journal

There is no journal addition with the Apple Health app. In the AutoSleep app, there is an option to add emoji tags or notes each day, which you can search back through in the future. It does not correlate with your sleep data - that’s up to you to figure out and track. 

Apple Watch Cost

The cost of the Apple watch depends on the model and band that you choose. The basic model of the newest Apple watch (Series 6, as of May 2021) is $399 USD plus shipping. The basic model comes with an aluminum case and silicone ‘sport’ band, in a variety of colors. If you’re looking to make a fashion statement or have it look like a higher end time piece, you can tailor it with a stainless steel case and Hermes leather band to the tune of $1399 USD. 

Our Apple Watch Experience

We find the user experience with the Apple Watch for sleep tracking to be much less enjoyable than the Whoop or the Oura. Having to vet third party applications and switch between multiple different apps to see our sleep data feels clunky and inefficient. We also feel that there is less consistency and cohesion between the different data points. 

Of the three devices and apps, the Apple apps miscalculate our sleep start and end times the most often and are the most challenging to modify/update manually to correct. 

On a final note, there is a reason why lots of people love their Apple Watches. There are many more options and ways to use the Apple Watch compared to the Whoop and Oura - including triaging your email, voice responding to texts, and acting as an actual watch. The Apple Watch feels like an extension of your phone, first and foremost, an activity tracker, second - and only with extra apps - and a sleep tracker as more of an afterthought. 


Oura Ring

The Oura Ring Device

The Oura ring is a titanium ring that you wear on your finger. Oura indicates that it does not matter which finger you wear it on, and you can switch it up as you see fit. Prior to purchase, Oura will send you a free ring sizing tool to ensure that you order the right fit. The ring is available in 4 colors - silver, black stealth (matte black) and gold. It is waterproof and the battery lasts for up to a week. 

Oura UX

The Oura App is the least complicated and easiest to use of the 3 devices. It prompts you to sync your device and walks you quickly through the features when you first install it.

On the home tab each morning, the app provides a readiness score, sleep score, and activity goal. From there you can click through for a deeper dive into each of these individual metrics. The app also makes recommendations and highlights any areas in which your sleep/recovery performance may be lacking.

Oura Sleep Score

The Oura sleep score is presented as a rating out of 100. This total score factors in 7 different metrics: 

  • Total sleep time
  • Restfulness (how much tossing and turning you did)
  • Sleep efficiency
  • Time spent in REM sleep
  • Time spent in deep sleep
  • Timing (what time you fell asleep and woke up & consistency with your normal schedule)
  • Sleep latency

Similar to the Whoop, the sleep score becomes more accurate over time, with consistent use, as the algorithm learns what is ‘normal’ for you and then starts to compare your nightly performance to previous patterns. 

Oura Sleep Stages

The Oura Ring tells you how much time you spend in REM and Deep sleep and indicates what percentage of your total sleep time was spent in each phase. In the sleep tab, there is also a graph that shows when you were in each phase of sleep during the night. 

Like the Whoop, it is unclear exactly how Oura determines what stage of sleep you are in. There are a couple of published studies comparing Oura to laboratory sleep studies, which show that it is consistent, but less accurate at predicting sleep stages than conventional sleep studies. 

Related articles for reference:

The Sleep of the Ring: Comparison of the ŌURASleep TrackerAgainst Polysomnography

Multi-Night Validation of a Sleep Tracking Ring in Adolescents Compared with a Research Actigraph and Polysomnography 

Oura Readiness Score

This is very different from how Whoop predicts your recovery. Since the Oura Readiness Score factors in so much of your historical data, you don’t see massive fluctuations from day to day. Instead, if you’re having a rough week with sleep and stress, your readiness will start trending downward. Similarly, if you’re really dialed in, the readiness will stay consistent or trend upwards.

Another feature of the Oura, which is reported in the readiness tab, is reporting of RHR and HRV for the whole night. We really love being able to see all of that data. It helps to see how quickly your HRH and HRV change overnight and we find this is useful for relating how our evening routines and behaviours affect our whole night of sleep and recovery. 

The Oura app also shows when you have reached your lowest RHR in the night. Ideally, it should be around 4am (or around the midpoint of your sleep) to coincide with the fluctuations of your sleep and stress hormones. If it’s later than that, closer to right when you wake up in the morning, it means that you were too metabolically active when you want to bed (ate or exercised too late in the day). If you reached your lowest RHR earlier, in the first couple of hours after you fall asleep, it’s a sign that you were really exhausted when you went to bed. 

Anecdotally, this is the metric that we find MOST correlates with how we FEEL in the morning. On days when we wake up feeling sluggish, we typically see that our lowest point in our RHR was right before we woke up. This is an indicator that we were not able to get into good quality deep sleep earlier in the night. And, man, can you feel it. 

Oura Activity Tracker

The Oura Ring automatically tracks steps taken, walking distance, and amount of movement and sedentary time throughout the day. It also gives you an ‘Active Calorie Burn’ goal to reach each day. There is an option to manually add a workout, with various activity categories. A recent upgrade to the app now automatically detects when it thinks you have done a workout, letting you confirm and categorize the activity. 

Though the app factors in activity from the previous day and two week trends in your Readiness Score, its insights are more basic than the Whoop and are limited to recommendations like “Prioritize recovery”, “Go Easy”, and “You’ve recovered well”.  

Oura Journal

There is an option to add tags to each day, and you can customize the tags that you use. This is something that you have to remember to do, as the app does not prompt you. If you consistently use the tags, you can then use the ‘Trends’ view in the app to see how your sleep and Readiness Scores are affected by a given factor, such as ‘alcohol’, ‘caffeine’, ‘ear plugs’, etc. 

The journaling and insights from different behaviours are less robust than the Whoop and require much more effort on the part of the user.  

Oura Cost

The Oura ring starts at $299 USD, for the silver and black options, and includes a charger. The gold and stealth options are $399 USD. 

Our Oura Experience

After months of using all 3 trackers, we have found that the Sleep and Readiness Scores from the Oura are the most reflective of how we actually feel. 

The Oura is our preferred tracker for sleep because it shows the whole night of HRV and RHR data, instead of a small snapshot. 

As an activity or fitness tracker, the Oura is not our favorite. Since we like to lift weights and use a pull up bar at the gym, we almost always have to take it off during our workouts. It does not have a way to use GPS or track outdoor runs/cycling etc. 

However, it can be synced with both Google Fit and Apple Health, to add more information and power to these platforms. 

As sleep and data nerds, we find the Oura ring to be good value and easy to use. It's a good looking, convenient sleep tracker that provides powerful sleep insights.

Summary Comparison Chart




Heart Rate Variability

Gives daily value based on readings taken at 3 different one minute readings each night.

Needs a third-party app for sleep insights.

Reports average from the last cycle of deep sleep.

Graphs HRV for the entire sleep duration.

Reports Night Average & Night Max

Resting Heart Rate

Reports daily average.

Reports average from the last cycle of deep sleep.

Graphs HR for the entire sleep duration.

Reports night Average, Night Minimum, and

Time minimum  reached.

REM Sleep

Needs a third-party app.



Deep Sleep

Needs a third-party app.



Respiratory Rate

Needs a third-party app.



Body Temperature




Sleep Disruptions

Needs a third-party app.



Total sleep time




Sleep latency

Needs a third-party app.



Sleep efficiency




Activity Tracker

Auto tracks steps, walking, standing time. 

Needs a third-party app for other activities. 



Journaling Feature

Needs a third-party app.


Must add





Battery Life

About 24hrs

About 44 hrs

**Does not need to be taken off to charge

Up to 7 days





Device Compatibility


Android & iOS

Android & iOS

App Compatibility

Many third-party iOS Apps

Only Whoop

Oura app, Google fit, Apple Health


Starts at $399 USD

Subscription - Starts at $30 USD per month, includes band

Starts at $299 USD


Final thoughts

The most powerful metrics reported from all of these sleep trackers are your overnight RHR, HRV, and Sleep Time. Sleep tracking technology is still lacking in its ability to accurately report sleep stages in simple consumer devices. Additional research has found this trend is not limited to the Whoop and Oura – it’s a challenge across all commercial sleep trackers. 

After months of wearing the Whoop band and the Oura Ring (we’re not including the Apple Watch here because it does not do REM and Deep sleep tracking in the Health app), we have noticed that the trends from both devices are reliable. While our time in different sleep stages is reported as being different in the two apps, they are consistent in how they differ. For example, my Oura always reports much less REM sleep than my Whoop does. Though I’m not sure which device is more accurate, what I do know is that when I get more REM sleep than normal on any night, both register a bit more.

We have read reviews of both Whoop and Oura that criticize the accuracy of the sleep stage reporting – and we think they are missing the point. You can still get great insights from monitoring your own trends, regardless of how perfectly accurate the measurement is, as long as the inaccuracy stays consistent – which it does.

All three devices are useful tools for anyone looking to better understand their body and their sleep quality. So, which sleep tracker should you buy?

Whoop is best for: 

Active people and athletes who want a robust system for tracking both activity and sleep & recovery. 

Apple Watch is best for: 

People who already have an Apple Watch who want to start tracking their sleep without purchasing another device. 

Oura is best for:

People who want robust sleep tracking and are less interested in using their device as a fitness tracker. We think the Oura Ring gives the best sleep related insights. It does a great job of tracking your physiology through the whole night. We don’t recommend it for people who do manual labor or for people who lift weights regularly and want to wear their fitness tracker at the gym.  

If you have a sleep tracker or other device that you love and think is as good or better, than any of these three, keep using it! We’d also love to expand our knowledge and experience - so please email us at with your insights. 

Sleep tight,
Dr. J 

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