I first tested the $99.95 Withings Sleep in 2018, when it was known as Nokia Sleep. It was an interesting concept at a time when most consumer sleep trackers were either absurdly expensive or worn on the wrist. It wasn’t perfect, but in the years since Withings left the Nokia umbrella, there have been enough changes to the Sleep that I wanted to test the device again to see what had changed – and which had not changed.
On the design side, almost nothing has changed. It’s still a 25-by-7.5-inch device that you plug into an outlet and then slide under your mattress at chest level. The gray fabric cover is still the same, except it now reads Withings instead of Nokia. The appeal here is that you can track your sleep by simply lying on your mattress like you always have – and without having to wear an uncomfortable device.
The configuration is also the same. You still need to pair your phone via Bluetooth and connect the device to Wi-Fi. Smart home integration via IFTTT hasn’t gone away, so you can still control your lights and thermostat. Overall, the bottom line is that the physical product and many of its features haven’t changed much.
What has changed, however, are the metrics it tracks and its overall accuracy. Withings now tracks breathing disorders in addition to snoring and can generate a PDF sleep diary that gives you an overview of your sleep patterns over time. Withings defines breathing disorders as “breaks in breathing patterns”, and less is better. That doesn’t mean it can diagnose sleep apnea, though. There’s a high-end version of Sleep called the Withings Sleep Analyzer, which claims to have medical-grade sleep apnea detection. It is also not available for sale in the United States, as it does not have FDA clearance. For the moment, the analyzer is a device reserved for the European Union.
However, in the sleep test, this distinction seemed like a matter of semantics. According to the Mayo Clinic, sleep apnea can be a serious sleep disorder characterized by repeated starts and stops of breathing — an interruption, if you will. Although there are explicit warnings that this is not a diagnostic device, it feels like Withings is getting awfully close to the line. This is especially true as snoring is a possible indicator of sleep apnea and sleep follows snoring.
Even so, in testing, breath interruptions and snore detection were quite accurate. The last time I tested the Sleep, it never detected my snoring, although my roommate insisted that she had heard me snoring loudly several times. I don’t snore as much these days – or as loudly; I know this because I logged my snoring through the Sleep Cycle app and the Samsung Galaxy Watch 4. But, this time around, the Withings Sleep was able to catch a few nights where I snored. This is a noticeable improvement over last time.
The Sleep Diary feature was also helpful, but be aware that it takes about a month to get a clear view of your sleep patterns. You can configure the log to report a custom time period or on a quarterly or monthly basis. In the report, you will find the average sleep heart rate, average sleep duration on weekdays and weekends, latency, efficiency, bedtime and wake-up time, as well as snoring-related statistics and respiratory interruptions. There’s also a visual representation of how long you’ve been in bed, how long you’ve been sleeping, and extended periods out of bed.
I can get this data from a number of sleep trackers, but even popular options like a Fitbit or the Oura Ring don’t let you easily view your habits over a long period of time – let alone provide you with averages in one place. You have to dive into individual menus and put them together that way. Some, like Fitbit, put advanced sleep data behind a paywall, and there’s no such issue here. The only thing I didn’t like about the sleep diary was how long it took to create it. Sometimes I had to try a second time because it sucked before I finished calculating. Again, this is a fairly comprehensive report, and it makes sense: the longer the time period, the longer it can take to generate.
In general, I liked the tweaks and improvements Withings added here. There were a few minor annoyances, however. For starters, syncing your data in the morning is slower than it should be. Sometimes I left my phone on the bed as I got up to start my morning chores. My data generally loaded without issue during this time, but there were two instances where I had to re-pair the device. The first was because my crafty dog knocked the plug out of the outlet. The second time the device just didn’t work and I don’t know why. Each time you re-pair the device, it takes an additional 10 minutes to recalibrate it to your mattress thickness. This is something to keep in mind if you choose to take this device on a trip.
In terms of tracking, the Sleep largely matched the Garmin Forerunner 255 — which I was testing simultaneously — and the Oura Ring. Sure, there were variations in my sleep scores and sleep stage data, but they weren’t far off the baseline. The only thing I would say Oura’s ring was better for was taking naps. Sleep always said my naps were an hour long, but when I tapped to see more info, it gave me data for an entire night’s sleep. So I wouldn’t give too much importance to those reports. Otherwise, I saw a big improvement in detecting when you’re in bed but not asleep and whenever you wake up and get out of bed in the middle of the night.
Overall, I’d say this is a great affordable option for anyone who hates wearing rings or trackers in bed. It’s not overly complicated, but at $100 you get a good set of features, especially if you’re someone who wants to view your sleep habits in a simple report. Plus, it’s great to see that Withings is still bringing new features and updates years later. There are still a few quirks to the device, but none so bad that I would tell people to “sleep on it”.
Photography by Victoria Song / The Verge