The $100 Withings Sleep (formerly known as the Nokia Sleep) is a sleep-tracking device which slips under your mattress, where it automatically records the depth and quality of your sleep, plus your heart rate, snoring and breathing throughout the night.
The device sends its data to the Withings smartphone app (iOS and Android), called Health Mate, where it can be combined with data collected from other devices sold by the French health tech company, like fitness-tracking smartwatches and connected scales. It also works perfectly with all devices sold under the Nokia Health name, made before Nokia sold the division back to Withings in 2018.
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Withings also allows the Sleep to talk with IFTTT (if this, then that), the smart home automation platform. This means, with a bit of configuring, you can have lights automatically switch on and off (or have your heating adjust) when you get in and out of bed.
Withings Sleep review: Hardware and Setup
The Sleep fits beneath your mattress, where it cannot be felt
Unlike some sleep trackers, like the Beddit which sits under your sheets but on top of the mattress, the Withings Sleep sits below the mattress. I hadn't realized this before unboxing the device, and was surprised by how the Sleep is sensitive enough to accurately detect the user's heartbeat, breathing and movement through the mattress.
Setting up the Sleep is a simple process which is explained with clear instructions inside the Health Mate app. When plugged into a wall outlet for the first time, the Sleep pops up on the Health Mate app; you are then shown how to position the Sleep so that it sits roughly below your chest as you sleep.
Next, you need to leave the Sleep alone for a few minutes while it calibrates to your bed. I first used the Sleep on a bed with a metal frame, but since I was only staying there for a few days I re-calibrated the Sleep for my own divan bed when I got home.
Once calibrated, the Sleep will automatically gather data every time you sleep in your bed. This can stretch the setup process over several days if you realize, having viewed the first night's data, that the Sleep isn't in the right location or position. This is because there is no way to start the tracking manually to check things are working properly; it'll only work when you actually sleep on it.
Fortunately, the Sleep worked for me right away. But if you share the bed with a partner, you might need to experiment to get the positioning just right. You can install a second Sleep if you and your partner both want to record data, with you each getting your own profile within the Health Mate app.
Being under the mattress, the Withings Sleep cannot be felt at all when in bed. It truly is a seamless addition to my self-quantifying routine, with no hardware to interact with at all.
Withings Sleep review: Software and Features
The Health Mate app is available for iOS and Android
The free Health Mate app presents you with a daily 'Sleep Score' out of 100, with a brief description, such as "restful night". The app also rates the depth and duration of your sleep, states how many interruptions you had during the night (resulting in you waking up), how long it took you to get to sleep, and how long you remained in bed after waking up in the morning.
Tapping on each of these metrics reveals more information, such as the exact times of the interruptions, the total time you spent in each stage of sleep (deep, REM, light), and how your stats compare to the average among Withings Sleep users.
A color-coded graph shows your sleep cycles over time, clearly highlighting when you were in REM, light and deep sleep, and when you woke up during the night, if at all.
A new feature added via a software update in early 2019 is breathing disturbance monitoring. Breathing disturbances are moments where you stop breathing during the night, and can be a sign of chronic snoring or a more serious health condition like sleep apnea. A graph shows you your nightly breathing disturbances (if any) and uses a color-coded chart to show how you compare to what's considered healthy.
Finally, the app shows your average heart rate for the night (below 60 bpm is considered healthy) and when you snored, if at all.
There's a lot of data here, but it is presented neatly and in a way which is easy to digest and understand. It is also easy to spot trends over time, which could help determine degrading or improving sleep quality over the weeks and months.
Withings Sleep review: Performance
Using the Sleep is a case of set-it-and-forget-it
Once set up and slept on, the Sleep sends a report of the previous night to the Health Mate app. I was always impressed to find the data ready and waiting for me when I opened the app; no need to wait while the data is transferred, as the transfer happens automatically when you wake up.
I liked how the Sleep worked automatically every night, but the lack of any manual control means it can get confused between sleep and being still but awake in bed - while reading or watching TV, for example. One evening, I watched something on my iPad for an hour in bed before going to sleep. The device plots this accurately, pretty much nailing the time I fell asleep; but because I had been in bed for a while beforehand, it thinks I spent 43 minutes trying to get to sleep, which lowered my score for the night.
You can manually edit the time you fell asleep and woke up at, which helps to fix this lack of understanding, but now my score was artificially high because the app thinks I fell asleep in zero minutes. Being able to tell the app what time I started trying to sleep would fix this, and seems like an obvious oversight on Withings' behalf.
I also wish the Withings Sleep had a form of alarm. Knowing what stage of sleep you are in, it's the perfect device for triggering a dynamic alarm, which could be set to wake the user up when they are least asleep. Sleep-tracking apps on phones, smartwatches and wearable fitness trackers do this, so it's a shame Withings hasn't added a smart alarm to its app.
Those small issues aside, the Withings Sleep is an impressive device. It feels like a better solution than sleeping with a smartwatch on my wrist or smartphone next to the pillow - especially as wearables tend to become uncomfortable and disrupt my sleep.
Withings Sleep review: Smart Home Integration
IFTTT integration brings smart home support
As I mentioned earlier, the Withing Sleep works with IFTTT, the smart home automation platform. There are only around 10 applets to pick from, but I've found them to be quite useful - just so long as you have the right devices in your home.
I have configured three applets to communicate between the Sleep and my Philips Hue smart lights. These applets - which you can find here - automatically switch my bedroom Hue light strip to a soft reading glow when I get into bed at night, then turn the bedroom light on dimly when I get out of bed during the night, and switch it off again when I get back in.
By tinkering with the timing of these applets (when they are active during the day and night) I have created a way to have a soft reading light in the evening, followed by a very dim light triggered if I need to get up during the night. Then, because these applets are all disabled by morning, the Hue lights perform their sunrise simulation as normal to wake me up. Additionally, the applets are automatically disabled during the day, so lying on the bed or having an afternoon nap won't control any lights.
These actions aren't instantaneous, unfortunately, and take around five seconds to be triggered. Chances are, you'll already be out of the bedroom by the time the lights come on; but if you have Hue lights in your bathroom you could include those with the applet and they should be illuminated just as you're usually fumbling around for the switch.
You can also create an applet to lower the temperature of your house when you get into bed, then warm it up again when you get out in the morning, but this only works with Nest thermostats for now.
Similarly, an applet can mute your smartphone when you get into bed, but it only works with Android handsets, not iPhones.
Withings Sleep review: Verdict
The Sleep slips under your mattress, where it cannot be seen or felt
Perhaps this is because I already use several Withings watches and a smart scale, but the company's Sleep has always appealed to me more than alternatives - including the Apple's-owned Beddit, which costs $50 more.
After sleeping on the Withings for a couple of weeks, I feel my initial positivity was justified. The Withings Sleep is a reliable and completely seamless way to record your sleep; you don't need to touch or wear anything, and the data it collects is ready to be viewed as soon as you grab your phone the next morning. It truly is a case of plug-in-and-forget, which is exactly how smart home and health tracking tech should work.
I felt the data it gathers is accurate - a claim reinforced by how its finding matched those of an Apple Watch I wore during the first couple of nights - and the information is displayed neatly in the Health Mate app. There is also an eight-week sleep improvement program in the app, which is free to use and offers advice on improving your sleep score over a two-month period.
When slotted into the rest of the Withings/Nokia ecosystem - or just used alongside one of the firm's smart scales - I really felt I was getting a good and useful overview of my health and daily routine. What one can actually do with sleep data remains up in the air, but personally I find it reassuring to quantify my tiredness; the Sleep and Health Mate app offer a visual starting point from which to improve. And, given we spend a third of our lives asleep - not to mention the numerous health issues associated with lack of sleep - that feels like $100 well spent.
- Automatic sleep tracking
- Totally seamless and no wearable required
- Health Mate is a great app
- Limited smart home integration
- Fairly expensive
- Lacking a smart alarm