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15 years ago, if you wanted to find out more about your sleep habits, your options would have been extremely limited. Options would have included a Fitbit with rudimentary sleep tracking (essentially a reverse-engineered pedometer), writing down your sleep/wake times in an old-fashioned paper journal (maybe a spreadsheet if you’re that way inclined), or if you want to go the whole hilt, you could spend a night in a professional sleep clinic.
Fast forward to 2020, and the consumer sleep technology industry has exploded. Fuelled by increased public interest in sleep as a serious health concern, there are now more ways than ever to track, monitor, analyse and optimize your sleep with the aid of electronic gadgets and gizmos.
In an extremely innovative field, entrepreneurs and startups have over the years packed sleep-monitoring technology into a dizzyingly broad range of devices and formats; apps, wristbands, headbands, radar technology devices, integrated mattresses and smart beds – you can even buy a pair of noise cancelling headphones that track your sleep!
But something else that’s happened in the sleep tech industry is a growing segmentation in the market that reflects quite different needs of consumers. Whilst historically sleep monitoring has been all about consumers wanting to know more about metrics such as time to fall asleep, sleep duration, and deep, light, REM sleep stages, there’s also a burgeoning industry looking at sleep monitoring from a completely different lens – the ability to track and monitor blood oxygen levels and heart rate – to inform users about their breathing functions during sleep, and consequently whether or not they may or may not be at risk of sleep apnea, which afflicts at least one in five adults in North America.
What is the Wellue O2Ring?
So, enter stage left, the Wellue 02Ring from Chinese health-tech company Shenzhen Viatom Technology which focusses on innovative medical products for the homecare and telemedicine market including pulse oximeters, EKG monitors, blood pressure monitors and tons more stuff. And in essence, the Wellue 02Ring is just a simple pulse oximeter, albeit one that’s well suited to taking measurements whilst you’re asleep.
What is pulse oximetry?
Pulse oximetry is a painless, noninvasive method of measuring the oxygen saturation in a person’s blood. It’s a routine medical procedure – a simple, quick and efficient way to quickly assess someone’s general health and it’s also used as a continuous measurement in critical care settings like emergency rooms or hospitals.
Pulse oximetry has become so widespread that blood oxygen saturation is sometimes referred to as the “fifth vital sign,” alongside temperature, blood pressure, pulse, and respiration rate—to gain insight into a person’s health status. Recently there’s been a surge in the popularity of home pulse oximeters because of the rise of the COVID-19 which can cause significant drops in blood oxygen saturation.
How does a pulse oximeter work?
A pulse oximeter is a small, electronic device that’s clipped onto a part of the body, usually your fingertip. The device emits a red light that shines onto your finger, passing through skin, tissue, fingernail and your blood. The red light gets absorbed by hemoglobin and deoxyhemoglobin and on the other side of your finger, a sensor detects the amount of light that passing through. This sensor reading is an estimate of the amount of oxygenated blood cells in your body and is expressed as a percentage measurement called SpO2, and a normal, healthy individual will have an Sp02 reading of between 95-100%.
Why is pulse oximetry useful for monitoring sleep?
Because Sp02 is essentially a measure of how well oxygen is being pumped around your body, pulse oximeters are clearly useful in countless diagnostic and monitoring situations. But for our purposes we’ll just concentrate on the applications for sleep health and particularly in identifying risk of sleep apnea.
Sleep apnea is an extremely common sleep disorder, which according to a study in the Lancet published last year, may affect a billion people round the world. Sleep apnea is characterised by repeated breathing interruptions during sleep. Risk factors for sleep apnea include being male, overweight, over 40 and/or having issues with the structure of your jawbone, tonsils, tongue, or anything else that can obstruct the breathing airways.
Severity can range from mild to chronic, and in the worst cases, people may stop breathing hundreds of times during the night, each apnea event lasting from a few seconds up to a few minutes. When this happens, the brain and body are starved of oxygen and the consequences of untreated sleep apnea can be extremely dire and lead to an increased risk of chronic conditions like stroke, heart attack, and even dementia.
Because this happens at night, the majority of sleep apnea cases are thought to be undiagnosed, because people just aren’t aware of what’s happening to them during their sleep. This is where a pulse oximeter can be indispensable, giving you feedback on your oxygen saturation levels during the night, and acting as a screening tool which will advise you on how and when to approach your doctor for further medical diagnostic advice.
Reference: The uses of overnight pulse oximetry
Caveat – a pulse oximeter is not a medical device
It’s important to make the distinction that consumer pulse oximeters like the Wellue O2 Ring should not be considered medical devices in themselves and are not intended to diagnose and/or treat medical conditions.
If you want to really find out if you have sleep apnea, there are only really two medically approved ways to find out – either with a Home Sleep Test (HST), or an overnight sleep study in a hospital or clinic. Both of these pathways depend on the patient having access to either medical insurance or money to cover the costs which can range from hundreds to thousands depending on the particular diagnostic tests required.
But that doesn’t invalidate using a device like the O2 ring. Consumer products like these encourage people to actively take an interest in their sleep health, and using the metrics from their devices, can then go on to make informed choices, and if necessary consult a medical professional. So, enough of the background, let’s take a look at the product itself.
O2 Ring: Product Overview
The Wellue O2Ring is a wearable sleep monitor that can track oxygen saturation (Sp02), heart rate and movement continuously whilst you sleep. Designed as a ring to be worn on the thumb or index finger, the O2 Ring claims to be the ‘lightest, smallest ring sensor for overnight [Sp02] continuous monitoring ‘.
When low oxygen level or abnormal heart-rate is detected, it silently vibrates, waking you up, alerting you to breathing interruptions during the night.
The wearable works as a standalone device, with a built in storage memory and OLED touchscreen, or alongside the companion ViHealth app, offering both real-time displays, as well as downloadable, detailed reports of nightly, weekly or long-term sleep data which you can download and share with your doctor.
As well as being able to take measurements while you sleep, the 02Ring can also be used for instant ‘spot’ readings and so offers benefits for a range of applications and conditions, not just sleep apnea, but snoring, asthma, COPD, athletes, pilots, pregnant women and possibly even an early warning for flu and Covid-like symptoms.
Price and Specifications
|Price||From $169 (Get 10% OFF with CODE: SLEEPGADGETS10)|
|Measurements taken||Oxygen level (Sp02), pulse rate, movement|
|Battery Life||12-16 hours continuous use|
|Connectivity||Bluetooth 4.0 BLE|
|Pulse Rate Range||30-250 bpm|
|Built-in Storage||4 user sessions (up to 10hrs each)|
|Warning Vibration||Low oxygen, high/low pulse rate|
|Measurement interval||1 second (in-app intervals 4secs )|
Take 10% Off Wellue 02 RingUSE COUPON CODE: SLEEPGADGETS10
Unboxing/ First Impressions
The packaging is simple and unfussy. Unwrapping the cellophane you’ll find the box for the ring. Sliding off the outer sleeve reveals a short foldout user guide, and tucked away down the side, a micro-USB cable for charging. That’s it for accessories.
The ring itself is nestled inside a faux-velvet- lined cardboard housing – no doubt trying to give you the impression you’ve just come back from a trip to Tiffanys. The most obvious thing about the ring is the clear semi-adhesive screen protector and removing it reveals the sleek, but futuristic aesthetics – the onyx black OLED display on top, and the stretchy silicon ring underneath.
The ring still had some charge left in it, which was impressive as a Covid-inspired postage delay meant it had been at least a couple of months since the box was mailed to me.
The ring is very tactile, solid, comfortable and nice to hold. I was quite surprised initially by the size. After trying other wearables like the new generation Oura ring, this thing seems pretty large by comparison, with the OLED spanning about half the length of my pinky finger.
The immediate compulsion to try it on is rewarded by the device automatically activating, and after around 5 seconds giving you a real-time readout of Sp02 and heart-rate. It’s a nice reassuring touch when something just works straight out of the box with no prompting.
So all in all, good first impressions, so let’s talk about the design and usability.
Most pulse oximeters you’ll find in a doctor’s surgery usually have what’s sometimes called a ‘duck bill’ sensor, which clips onto the end of your fingertip, and then a wire sends this information to a screen for a readout. This design has been around for decades, but with the O2Ring, Viatom wanted to ensure their device would be suitable to wear in bed all night without falling off, and at the same time, comfortable enough not to disturb your sleep.
The result of these efforts is a form factor of an oversized signet ring – which makes the device unique in its product class, and although large for a piece of jewellery, the O2 Ring is actually the smallest, ‘medical-grade’ oximeter that can operate continuously throughout whole night.
I actually quite like the look and feel of the device. The jet-black OLED screen lends a minimalist, futuristic aesthetic, whilst the grey, rubberized silicone is soft to the touch. The ring is a one-size-fits-all affair, and to achieve this there’s an inner ring to help keep the device in place and stop it spinning around your digit.
The display is simple, pleasing and informative, but only shows a limited amount of information; your real-time heart rate, Sp02, battery level and the time. All other metrics are only available in the app.
The O2 ring uses the same ‘transmissive‘ pulse oximetry technology as medical-grade pulse oximeters. Transmissive oximeters require light to be shone through the fingertip, and then a sensor on the other side will detect the oxygen saturation. So inside the ring, the LED light source has a capacitive surface which automatically lights up as soon as you wear it – hence there’s no on/off button, or fiddling with an app to get started. After a while the display times out but tapping the circle icon wakes the screen up again so you can get a real time readout.
There’s a single micro-USB port for charging hidden behind a rubberized flap. Wireless charging would have been nice, but this I’m guessing would add to the size and weight.
We’ll cover the app later, but one of the interesting design features is that the 02Ring is ‘always on’ in the sense that as soon as you put the device on, it starts to record your biodata onto the built-in storage, a solid-state memory chip that can hold 4 sessions of data, up to 10 hours each. So, this means you don’t need to connect the device to your app every day if you don’t want to as the data will automatically upload as soon as you fire up your device.
Comfort wise, the ring seems bulky when you first put it on, but after a while you hardly notice it. Wellue recommends that you wear the ring on a thick finger, – ideally your thumb or index, to get a good fit – and curiously, they say not to use your middle finger…
I tried the ring in various situations, in bed, taking a nap, doing chores around the house, – I even went out running a few times wearing the ring – and whilst it’s not exactly discreet, it doesn’t get in the way like a traditional oximeter would, and pretty much allows you to carry on your normal daily (or nightly) tasks without interruption.
I worried that wearing the ring in bed would mean it slipping off and getting intermittent readings, but this didn’t prove to be the case, at least to my knowledge when reviewing my sleep reports.
Setup and installation
Good news is that the O2 ring is very much designed as a plug and play device. As long as the device has some charge you can use it straight away – for instance as a standalone device to take spot readings of Sp02, pulse rate.
To do so, simply place on your thumb or index finger. As soon as you do so, the capacitive sensor inside detects contact with your skin, the device powers on automatically, and then after around 5 seconds, you get a readout of your Sp02 and heart rate on the device screen.
But of more interest to users will be the continuous monitoring applications. For those wanting to know about their breathing during sleep, O2 Ring can be set to give off a vibration warning to gently wake you when the Sp02 level drops below a predetermined percentage. To do anything more than simple spot testing, you’ll need to install the companion smart phone app ViHealth.
Using the app
Don’t be put off by the lousy 2.4 star rating on Google Play Store. Yes, the app is quite basic, and utilitarian, but I found it to be pretty stable, no crashes or sync problems for me on my Galaxy S20.
Once you’ve installed the app, simply switch on your Bluetooth and then tap the O2 Ring’s circle icon to wake it up, and you’ll see your ring as a connected device, alongside any other Bluetooth Viatom devices you own. Handily there’s no pairing or codes to enter, the app is set to auto-discover your device, and this seemed to work very well.
Once you’re in the app, there are three main tabs to be concerned with -History, Dashboard and Settings
There’s a decent amount of tweakability in the app settings. To list them off, you can set thresholds for both Sp02 and Pulse rate to notify you with a vibration alert when you fall above or below a certain limit.
You can also choose one of three vibration intensities, depending on how light/heavy a sleeper you are. You can also choose options for the screen – Always On, or wake to touch, you can choose one of 3 screen brightnesses. Plus you also get a handy option to do a factory reset should you run into serious problems.
If you want to have a continous live readout of your Sp02 and pulse rate, click on the app’s Dashboard tab to get the real-time sensor readings from the ring. As well as the main metrics you also get a score for PI or Perfusion Index, which is essentially a measure of signal strength which can be improved by trying a different finger or ring position.
Finally there’s the history tab. This is of interest to anyone who wants to view their overnight data on your phone/tablet screen, export your data via CSV or share your sleep report with a medical professional for further analysis.
The History section works on the basis of user sessions. What this means in practice is that every time you use the ring, it stores the data internally, then, in the morning, or whenever you next connect via Bluetooth to your phone, the ring automatically uploads your sleep data, syncing it with the app for display and/or analysis.
Hence, each users session is presented in a list in the app, and clicking on each one will reveal further metrics. At the top of the screen you get a summary of recording time, various Sp02 readouts, average pulse rate, and a proprietary ’02 Score’.
Underneath this you have 3 graphs, for Sp02, Pulse Rate and Motion. You can zoom right in on the timeline, down to an interval in seconds – very useful for identifying the exact time of specific events.
At the top of the screen you have some sharing, naming and export options. You can choose to export the screen as a PDF or in CSV format which gives you a very detailed 4 second interval spreadsheet where, if you’re inclined, you can do some real serious number crunching.
With the 02Ring Wellue have cleverly pitched for a niche market here. They haven’t tried to produce a sleep wearable with 1001 functions, sleep staging, smart alarms and all that other fancy stuff….. Instead they’ve built on the knowledge and experience of what they do best – creating high-quality health monitoring devices for the consumer market – and developed a relatively simple, reliable and ergonomic sleep monitor that focusses on oxygen saturation and heart-rate.
The most obvious application for potential buyers is an ‘early warning’ system to detect low oxygen events during the night, which may indicate a risk of sleep apnea. With the ability to record abnormal events, and produce detailed reports, 02Ring can give your doctor an additional level of insight into your sleep health, potentially saving a lot of the hassle and costs involved in traditional diagnostic pathways like home screening tests.
The vibration alert is a handy feature, waking you up if you happen to drop below a certain Sp02 level. Of course, if this happens all the time, you’re advised to seek professional help – but in the short term, it may at least provide some relief and prompt you to wake and shift sleeping positions. But you might also find the alert useful if you’re a pilot or high-altitude climber, pregnant, or suffering from COPD or some other respiratory disease.
Comfort and ergonomics are good. The ring feels solid and well-engineered. I really like the fact that you’ve got onboard storage and you don’t have to fire up the app, or even press any buttons – you literally just put the ring on and you’re ready to go. Battery life is OK but not stellar. What would have been awesome if wireless charging, but I’m guessing this would have added to the weigh and bulk.
The app, as we described is pretty bland and utilitarian, but I actually quite liked the unpretentiousness of it. The main use of the app is to upload, view and export your sleep data and for this it’s perfectly fit for purpose, didn’t crash on me as others have reported.
My gripes? Well, it would be nice to have an accurate on-board battery indicator – a couple of times the ring stopped mid-sleep because I misjudged the battery life. Also, I think the handling of user sessions could be slicker. Right now, even if you put the ring on for a minute or so for testing, it counts as a session – the upshot being you end up with a whole load of junk data in your app dashboard when this is automatically uploaded.
But overall IMO, the Wellu 02Ring, Viatom is a really nice wearable that’s fuss free, but able to provide reliable Sp02 and pulse rate measurements throughout the night. Recommended 👍
02Ring costs $169 and you can save 10% by using our coupon code below.