Wellue O2Ring, a Compact Night Oxymeter Review

Wellue O2Ring, a Compact Night Oxymeter Review

Being a Geek often means that you are constantly looking for better numbers. Not only faster CPUs or more memory, but often you also want to track specific metrics about your health. The Apple Watch does many of those automatically, but if you are looking to see the impact of various life events on your health, you often need a more precise and specific product.

I am suffering from sleep apnea and have tried the CPAP machines, however, I was never able to sleep with such a device. The fallback plan was to use a special mouthpiece that brings my jaw forward and opens my airways. The only metric I had to go on was that it eliminated my snoring. However, I still wondered if it actually allowed me to get enough oxygen as I had no way to measure this. Until now!

The O2Ring by Wellue is an oximeter outfitted inside a ring-shaped device that you wear all night and it tracks your blood oxygen levels every second you wear the device.


The unboxing experience is simple and clean. You immediately see the O2Ring that comes as a rounded display set on a rubber ring. The shape reminds me of the 80s “feeling stones” rings that could read your emotions and change colors based on it. It’s about the same size but a bit thicker.

The rubber ring feels very fragile, and after trying to fit it on my thumb, I was barely able to set it there. Tried other fingers like my ring finger and it was not comfortable. It cut the circulation after a few minutes. I was suggested to use the pinky finger as any finger will work fine.

This is much more comfortable and I can wear it all night without discomfort or feeling I will break it by stretching it too much. The size of the device is not large, but sometimes it can get in the way and a few times when resetting my pillow I felt like I almost ripped it out. These times I wished it was more compact!

The display is a nice little display that displays your recorded O2 level in percent as well as your heart pulse rate. Easy to see and not disturbed during the night. You could spot some of the red light leaks around your fingers at times, but it was never enough to wake me or my wife during the night.


  • Transmissive oximetry technology
  • 4 second-recording intervals
  • 4 sessions of 10 hours recording memory, unlimited datasets in app
  • lots of customization options
  • report generation, CSV, PDF and binary exports
  • compatible with Apple Health
  • FDA listed


I’ve tried it for many nights and I also tried to use it when I had a different routine to see how it would affect my oxygen level during the night. I’ve always worn my mouthpiece for sleep apnea so that I could finally know for sure if the mouthpiece worked or not.

First, let’s get this out of the way.

This is not a diagnostic tool as with all consumer oximeter, there is a ±4% accuracy buffer, so this means that if the device reports 90% you could be anywhere between 86% and 94%. You can use this information to start discussing your situation with healthcare professionals but this data should not be used as final diagnostic data to define a treatment or medication.

The device is FDA listed which means that it’s known by the FDA but not that it was tested or approved by the FDA. The manufacturer is registered and so is the device. Here’s the FDA listing for you to review. Class 2 means that devices in that category “require some regulatory control of safety and effectiveness.” This basically means that it’s a good tool, but not a medically approved diagnostic tool.

Battery Life

I put it on when I go to sleep and take it off when I get out of bed. I tried to capture more than one night on a single charge, but I was not able to complete the second night in full. They advertise up to 16h on a full charge, but I was able to get exactly 15h of recording over two nights.

Even if it dies during the night, it still keeps the partial night data and you lose nothing of what was recorded.

Data Syncing

In the morning, I would put it back on and open the iOS app to sync the data. It takes a reasonable amount of time to sync via Bluetooth all the data. About 12-15 seconds for a full night. It also syncs very short periods when I just put it on to sync the data or see my current heart rate. I usually delete those and only keep full-night data sets.

They advertise 4 groups of 10 hours, so about 40 hours of recording on the device itself, but I never reached that. I usually sync it after one or two nights. And unlimited storage inside the mobile application.

Once synced, you can see the reports and lots of interesting details like the total time < 90%, the drops over 4%, and the number of drops per recording session. You even have an O2 Score that can be an easy metric to track and see how good you were oxygenated during the night. The average heart rate will also help you to see if you are putting unnecessary strain on your body because of a sleep condition like sleep apnea. I love that you can add notes to your recording session, you can use this to note things like at what time you got to sleep, or if you have been drinking alcohol or coffee the night prior. This is helpful to track as you will forget.

Warning and Alerts

There is a feature where you can set a limit and if it is reached or passed the O2Ring will alert you and note it in the data set. This is useful if you want to be woken up by the vibration if you enter a dangerous zone. Also, if you keep the app opened, the app can also alert you audibly.

Example of a bad night

Personally, I never reached the default threshold they set at the factory. Thankfully, this means even at night where I get many O2 drops, it never drops to dangerous levels. Most probably because of my mouthpiece, though. I did not want to start snoring again so I did not stop wearing it as it will mess with my wife’s sleep.


The reports can be exported as PDF and shared with your healthcare specialist, but at the same time it can sync your data to Apple Health. I have enabled this as I also track my blood pressure with a non-smart device where I enter my systolic, diastolic pressure and heart rate using a custom iOS Shortcut I wrote to quickly enter the data in Apple Health.

O2Ring Mobile App Report Exporting

This way I have my night oxygen level, night heart rate, resting heart rate when I take my blood pressure and my blood pressure, all in the same app. I would also recommend looking at the Heart Report app on iOS, it has very customizable report generation that can also be shared with your doctor. You can choose what metric to include to make them more useful.


After testing the O2Ring for many, many nights I must say that I found the experience very good! It’s not one of the most expensive ring-type devices, and it does not all the things, but it does one thing and one thing well. Its tracking is efficient and it is very simple to operate. I kind of wish it was slimmer not to get caught in my pillow or sheets while I sleep, though. And its 15-hour battery life is not enough as often, I would set it and did not realize it was not fully charged and only captured 3 or 4 hours of data.

If you are looking for more insights into your blood oxygen level, the O2Ring is a great device to do so. Its reporting is quite good, and adding notes can help you see what you change in your routine and how it affects your sleep quality. For me it was most of all a way to see if my mouthpiece was actually working for my sleep apnea and I’m happy to report it does work as on regular nights, my O2 level does not drop significantly.

There are ways to make this little device better, though! First of all, ditch the MicroUSB port for a USB-C port. Make it slimmer so it’s more of a profile design, it will probably be less in the way of sheets and pillows. And make it so that the hardware is better optimized for longer battery life! 15 hours is not enough, try to aim for at least 24h which would be about 3 nights of sleep.

Trouble Sleeping? The Wellue SleepU Sleep Oxygen Monitor Comes!

Trouble Sleeping? The Wellue SleepU Sleep Oxygen Monitor Comes!

You are sleeping and dreaming about unicorns, but do you know that your breath may stop and there may be a lack of oxygen in the blood, and you may be suffering from obstructive sleep apnea (OSA). Since normally people do not really experience symptoms, just wake up tired and feel sleepy during the day, it is not easy to detect it in its first phase.

Yet at least one in five adults who snore suffer from OSA in the US, usually, sleep apnea patients are surprised when they are diagnosed with this condition. Their airways are temporarily closed, preventing breathing, and they breathe less oxygen. These apneas can happen hundreds of times per night, apnea might even generate hypertension, heart disease, brain attacks, or diabetes.

The SleepU sleep oxygen monitor is designed for snorers and people suffering from OSA. It tracks your blood oxygen and heart rate level as well as your body movements. It can tell whether it is worth investigating sleep apnea further with a health professional. This is cost-effective, whereas diagnostic tests require overnight stays at a sleep lab and can cost thousands of dollars. Using SleepU can prevent you from making those unnecessary trips to a sleep lab, or alert you to the fact that you may need to visit them. Its adjustable vibration alert in the patented ring sensor will nudge you to change position to let you breathe more oxygen and sleep better.

The SleepU is USB disk-sized and equipped with a ring sensor to track blood oxygen level and heart rate. Unlike other fitness wearables tracking blood oxygen levels as part of a more extensive feature, SleepU exists solely to monitor your sleep blood oxygen. It is transmissive oximetry and measures blood oxygen level with medical-grade accuracy, whereas other wearable fitness devices utilize reflectance pulse oximetry. Usually, hospitals use transmissive oximetry, and this is where SleepU sets itself apart from main consumer-oriented sleep tracking devices.

How can you benefit from smart vibration?

SleepU has a unique design with a vibrator built in its ring sensor rather than the main unit, which makes it suitable for whole night’s sleep. When your blood oxygen level drops below your preset level (e.g. below 90%), the ring sensor will vibrate and stir you to wake up gently, remind you to change your position, helping you to reopen your airway to reduce snoring and breathe more oxygen.

If you are reluctant to wear a ring on your finger in bed because you consider it will disturb your sleep, I have to tell you that the SleepU sleep oxygen monitor is soft and comfortable to wear on. Since other devices usually cover your whole finger, oppressing your finger, making it numb and sweaty, and are easy to fall off from your finger, SleepU feels like wearing nothing.

The silent vibration instead of audible beeping doesn’t disturb your partner. You can adjust vibration intensity and threshold in App to fit you best. So the smart vibration function is useful for everyone, but it is especially useful for people who snore and those who have to live with sleep apnea, as well as their partners who sleep with them.

Is my CPAP machine effective?

 tracks SpO2 and heart rate overnight, it helps you to see whether the CPAP machine or oxygenator is effective and provides more info for therapy.

How to operate?

Simply wear it on your wrist overnight, no need to press a button, it records O2 saturation and heart rate automatically. No need to connect with your phone as it works even when not connected: 4 sessions will be stored in the device while the data will sync once it is connected. Absolutely, you can also connect SleepU with your smartphone or tablet while using, to watch your real-time SpO2 and heart rate.

Sleep insight with ViHealth APP

The next morning, you wake up, take off the device and enter the ViHealth APP to view the detailed report. You will see your overnight blood oxygen level, how many times your oxygen drops, how long your oxygen is below 90%, heart rate, body movement, and O2 score. O2 score is an easy and simple index to tell if your SpO2 is healthy while sleeping. It is calculated based on the drop time and how severe it drops, the higher the better. You can also log notes to record your comments, such as lifestyle or therapy. Or share overnight oximetry data and trends with doctors or friends for advice.

Share PC report with a doctor

With the included cable, you can connect the device to your PC or laptop, upload your overnight oximetry data to the PC software, export sleep report, save it as PDF or CSV format, share unlimited reports to your doctor or friends, and it is totally free!  

Take it everywhere with you

SleepU is USB rechargeable, working up to two nights on one charge. It can not work for a week like other fitness or sleep tracker, as the ring sensor continuously tracks your overnight oxygen saturation every second, that’s to say it will not ignore your blood oxygen event per second. As we know, their founders have over ten years of experience in medical device R&D.

If you suffer from snoring or sleep apnea, and you are tired of others constantly reminding you of it and giving you silly pieces of advice on how to deal with it, you should certainly consider trying the SleepU sleep oxygen monitor. As the device is certainly the most convenient tracker for measuring SpO2 during sleep.

Source: gadgets-reviews.com

Can sleep apnea kill someone?

Can sleep apnea kill someone?

Yes, you could not avoid the death threat by sleep apnea.

The Murderer of Princess Leia

Christmas in 2016, Princess Leia, Carrie Fisher, left us forever. Star Wars official commented to her: “She’s Princess Leia all over the world and our most special friend…” Her death is enough to make Hollywood and all the fans indulge in grief for a long time. According to the report of the LA County Coroner’s Office, the causes of death were listed as“sleep apnea, atherosclerotic heart disease, drug use”.

This article emphasizes that sleep apnea is not a one-off lethal blow to human beings, but the pain of sleep disorder just like chronic killing for people’s life.

What are the signs of sleep apnea?

If you feel tired even after a full night’s sleep if you or someone you loved snores loudly and frequently have incomprehensible and persistent high blood pressure, experiences gasping at night suffers fatigue at daytime or awakens with a dry mouth, or a morning headache, please do not perfunctorily treat the possibility you might have sleep apnea.

What causes sleep apnea?

A recent study from AASM estimated that almost 30 million adults in the U.S. have sleep apnea. More people began to pay attention to what causes apnea. Firstly you should know there are three origins of sleep apnea.

Obstructive sleep apnea, the more common form that occurs when throat muscles relax.

Central sleep apnea, which occurs when your brain doesn’t send proper signals to the muscles that control breathing.

Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, occurs when someone has both obstructive sleep apnea and central sleep apnea.

The following data show the severity of obstructive sleep apnea.

*Data from Article (PDF Available) in Journal of the Saudi Heart Association 179(4) · March 2015 with 214 Reads DOI: 10.1016/j.jsha.2015.03.004

For individuals, should think about how to reduce the occurrence of sleep apnea syndrome.

Here are some effective ways to find the sources of sleep apnea.


Smoking can increase the possibility of inflammation and fluid retention in the upper airway. Smokers are more likely to get sleep apnea than those who do not smoke.


The Elderly and middle-aged have a higher risk of OSA. If you occur a sleep disorder at that age, please check your body in time.

3)Heart Diseases

Snoring may lead to cardiopathy, such as pulmonary heart disease. When the body is in a chronic intermittent hypoxia and acidosis state for a long time, which actually affects the heart. Sleep O2 which is an easy-to-wear product helps you record heart rate and blood oxygen during sleep, effectively helps you understand the quality of sleep to judge health.

4)Neck obesity

People with thicker necks might have narrower airways. Obesity patients with neck fat deposition can lead to upper respiratory obstruction in varying degrees.

5)Alcohol and Sedative

These substances make muscles in your throat relax, which can worsen obstructive sleep apnea.

How to treat sleep apnea?


Continuous positive airway pressure is the preferred method for the treatment of OSA. By providing adequate positive airway pressure to keep the respiratory tract unobstructed, symptoms can be alleviated and sleep quality can be improved.

2)Blood Oxygen and Heart Rate Monitoring

For healthy people, it is a good habit to regularly check the various functions of the body. Especially for patients with sleep disorders, the blood oxygen value during sleep is helpful to check their health status in time.

3)Weight and Diet Control

For overweight patients, diet therapy and exercise are more reasonable ways to lose weight, it’s best to keep your BMI within 24. On the other hand, it’s better not to drink and take sedatives.

Sleep, air, food, and water constitute the necessities of human existence. Adequate sleep enhances immunity, improves attention, and ensures physical vitality.

Through correct diagnosis and active treatment, hope you can recover your health as soon as possible.