A Ring and a Smart Bed Tracked My Sleep for 30 Nights. Here's What I Learned

Did you know CNET has a dedicated sleep team? Over the years, we’ve tested around 350 mattresses from dozens of brands. We’ve tried numerous bedding items, including pillows, sheets, blankets, comforters and more. We’ve researched and reviewed countless sleep-related products, from white noise machines and sleep masks to supplements and bedtime mocktails. If there’s an obscure “sleep hack” trending on social media, you can bet we’ve given it a shot.

We aim to sort through the overwhelming amount of sleep-related information available online to find what works — and help you avoid the things that don’t.

Everyone has varying health needs and sleep preferences, so there’s no one-size-fits-all approach to enhancing sleep quality. Still, we do our best to back our conclusions with actual sleep data, which is why it’s essential for us to use accurate sleep trackers. Our CNET sleep editors have tested various trackers over the years to find those that work best for each of us.

Types of sleep trackers

The most accurate sleep test is a polysomnography, which is conducted in a lab. It uses sensors to monitor physiological factors such as brain waves, eye movements, heart rate, etc. It’s extremely precise — but it’s not practical for everyday use. Most people who receive a polysomnography only do so because they’re being tested for a sleep disorder.

While not as accurate as PSG and unable to diagnose sleep disorders, many other types of sleep trackers are available for everyday use. They come in all shapes and sizes, from wearable rings and watches to mattress covers or pads.

Carlos Nunez, MD, chief medical officer at Resmed, explains, “Many wearable devices allow you to track your sleep patterns, such as bedtime, wake time, how often you wake up at night and some even track your sleep stages, like REM. Tracking these metrics over time can offer insights into the quality of your sleep health and empower users to make lifestyle changes to improve sleep and overall health.”

As part of our 30-night mattress testing series, my partner and fellow CNET sleep expert Dillon and I have tested several trackers, including Whoop, Apple Watch, Garmin, Eight Sleep and Oura. We’ve found wearables generally more accurate than devices you lie on, such as sleep tracking bed frames or mattress covers. Given that information, I have to admit that I was surprised by the results of our experiment testing the Oura Ring against our Sleep Number smart bed.

Comparing Oura and Sleep Number

Dillon and I recently tested the Sleep Number ClimateCool smart bed. This high-tech setup uses integrated sensors and SleepIQ technology to monitor body movements, sleep data and biosignals such as heart rate, breath rate and heart rate variability.

Read more: 90-Night Review of the Sleep Number ClimateCool Smart Bed

It tracks sleep metrics such as total time in bed, restful sleep, restlessness, bed exits and the times you fall asleep and wake up. The Sleep Number app collects and displays all this information, providing actionable insights and tips to help you improve your sleep quality.

Dillon and I began wearing the Oura Ring 4 while testing our Sleep Number bed. This allowed us to compare and contrast our sleep data and assess the accuracy of both.

Oura is widely considered one of the most precise wearables for tracking sleep, thanks to its placement on your finger near the radial artery for heart rate sensing. It tracks more than sleep, monitoring your fitness and activity, menstrual cycle, stress levels and more. For this review, I’ll focus on the sleep and biosignals offered by each. 

Oura offers a bit more detailed sleep data than Sleep Number, including the time spent in light, REM and deep sleep. Knowing when and how much time you spend in each stage provides valuable insights into your overall sleep quality, especially if you struggle with insomnia or other sleep disorders.

The symptoms of insufficient REM and deep sleep are similar. Oura’s breakdown of these sleep phases can provide more helpful information if you struggle to get quality rest. However, it’s important to remember that you shouldn’t try to interpret this data on your own.

“If you’re interested in more advanced data like REM versus deep sleep, sleep apnea detection or unusual breathing patterns, consult your doctor. Sleep trackers are a helpful tool, but not diagnostic devices. Medical guidance is essential for interpreting deeper metrics or addressing potential sleep health concerns,” explains Nunez.

Sleep trackers compared

Sleep Number vs. Oura Ring 4

Metrics	Oura Ring	Sleep Number
Overall sleep score	✓	✓
Total sleep time	✓	✓
Time awake	✓	✓
Time in bed	✓	✓
Sleep latency	✓	✓
Heart rate variability	✓	✓
Heart rate	✓	✓
Respiratory rate	✓	✓
Movement	✓	✓
Helpful insights	✓	✓
Recovery index	✓	x
Light sleep	✓	x
REM sleep	✓	x
Sleep efficiency	✓	x
Body temperature	✓	x
Blood oxygen	✓	x
Readiness score	✓	x
Bed exit	x	✓

At the beginning of our test, I didn’t have high expectations for Sleep Number’s tracking capabilities. However, when comparing the numbers with Oura, the results were surprisingly similar (for the most part).

As you can see in the nightly sample below, Oura reported 6 hours and 42 hours of total sleep, while Sleep Number reported 6 hours and 44 minutes. Oura said I spent 44 minutes awake, while Sleep Number reported 38 minutes of restlessness. While it’s hard to pinpoint the exact moment on either app, both Sleep Number and Oura reported my sleep and wake times within minutes of each other.

Oura indicated my total time in bed was 7 hours and 25 minutes, while Sleep Number noted 7 hours and 35 minutes. Sleep Number gave me a SleepIQ score of 80; Oura gave me a 78.

As expected, there were nights when the data did not match this well. In those scenarios, Sleep Number almost always displayed the more generous sleep scores and total time slept. Part of this discrepancy is because the Sleep Number smart bed occasionally assumes I’ve fallen asleep while watching television or reading, while Oura recognizes I have not yet entered dreamland. The bed may sometimes mistake Dillon’s body movements or our dog’s as mine, whereas our Oura rings don’t have that issue.

Read more: I Tested Three Sleep Trackers for 30 Days. Here’s the One I’d Actually Use

Sleep data compared

External factors occasionally affected our sleep quality, resulting in data that didn’t accurately reflect Oura or Sleep Number’s tracking capabilities. An example is when I’d fall asleep on the couch and then move to the bed in the middle of the night. There were a few nights when I put my ring on its charger and forgot to put it back on before falling asleep. Additionally, factors like illness or menstrual cramps sometimes make me uncomfortable enough to sleep somewhere other than our smart bed.

I excluded these nights to ensure the accuracy of this comparison. As a result, the sleep data presented here is not perfectly consecutive. Instead, to paint a better picture of how they track, it includes 30 nights of solid sleep on our Sleep Number smart bed while wearing Oura.

For 30 nights using both sleep trackers, the average total sleep reported was only one minute apart: 7 hours and 35 minutes according to Oura, and 7 hours and 36 minutes according to Sleep Number. Both reported an average of exactly 1 hour of restlessness or time awake per night. Sleep Number gave me an average sleep score of 86, and Oura gave me 82.

The health metrics tracked were also similar: Sleep Number reported my average resting heart rate as 53, and Oura indicated it as 52. Both trackers registered an average breath rate of 17.

Oura reported my average heart rate variability to be 64, while Sleep Number reported it as 124. This discrepancy isn’t necessarily because one brand is more accurate than the other, but because they calculate HRV differently. Both measure the time intervals between heartbeats throughout the night, but Oura uses a method called Root Mean Square of Successive Differences, while Sleep Number uses Standard Deviation of NN Intervals.

Regardless of how it’s calculated, higher HRV numbers are considered better, indicating good recovery and physical adaptability. Lower HRV numbers can be indicative of high stress levels, dehydration, alcohol consumption, poor sleep and more.

Why does tracking your sleep matter?

As Vanessa Hill, PhD, sleep research and specialist, explains, “Tracking your sleep can offer helpful insights into what happens after your head hits the pillow. For many of us, sleep can feel poor quality, maybe because of fragmented sleep or nighttime awakenings. Tracking can show whether you’re actually getting the recommended 7 to 9 hours a night.”

Observing your biosignals over time helps explain how your habits and lifestyle impact your sleep quality and patterns. For instance, my sleep quality on nights after consuming alcohol, not exercising during the day or going to bed later than usual is always worse, and it’s reflected in my lower HRV numbers on both trackers.

“What’s more valuable than a single night’s data is looking at sleep trends over time. A month or more of sleep tracking gives a better picture of your overall sleep health,” adds Hill.

If you’re just beginning your sleep tracking journey, making sense of all the numbers can be overwhelming. Nunez recommends starting with the following basics to help you build a consistent sleep routine and improve your sleep health overall:

• Sleep-wake times: Track what time you go to bed and wake up each day. Research shows that a consistent sleep schedule is key to improved focus, productivity and mood. 
• Total sleep duration: Aim for the recommended 7-8 hours of sleep each night.
• Time awake during the night: Frequent disruptions may signal restlessness or a potential health condition worth exploring with a medical professional. 
• Sleep interruptions: Noting events like snoring or movement can provide added context to your sleep quality. 
• Trends over time: Focus on patterns, not a single night’s data, to make more meaningful lifestyle changes.  

What sleep tracker should you use?

The type of sleep tracker you should use largely depends on your personal preferences and the health information you’re looking to uncover. If you’re not a fan of wearing a device to bed, such as a wristband or ring, consider a sleep-tracking mattress cover or pad like the Withings Sleep Tracking Mat, which was chosen as the best non-wearable tracker by our CNET sleep editors.

Nunez explains, “When considering a sleep tracker, it’s important to note there is no one-size-fits-all. When choosing one, you can consider: 

• Comfort: You need to be able to easily sleep in it consistently.  
• Compatibility: Check that it works well with your smartphone or other devices to access the data without challenges. 
• Reliability: Some devices have been well-tested and approved by the FDA for sleep monitoring, while others are more general consumer products. 
• Privacy: Understand how your data is stored and shared.  

Ultimately, the best tracker is one you’ll wear regularly, and that makes accessing and understanding your data simple.”

The bottom line

If you have a Sleep Number bed and are wondering how accurate the sensors are, I’m pleased to share that they appear pretty dang precise. I had not been expecting the results of this 30-night comparison between the Oura Ring 4 and Sleep Number ClimateCool smart bed to be so similar. Still, there’s much more room for error with trackers like smart beds and mattress covers compared to a wearable worn tightly on your body. 

If you’re looking for one of the more accurate sleep trackers, I recommend opting for a wearable like Oura or Whoop — but as Hill put it, “Choosing a sleep tracker really comes down to comfort and budget. Choose what works best for you, including something you’ll actually use.”