Sleeping well has become one of modern life’s biggest challenges. Between screens, irregular schedules and stress, more and more people feel like they’re not getting the rest they need. As such, it’s no surprise that recent years have seen the proliferation of tools designed for sleep analysis: smart watches, rings, sensors placed under the mattress and mobile apps that promise to measure how we sleep, and help us to improve our rest.
But do they actually work? Such devices can be useful, but they do come with significant caveats. Though they offer interesting information on our sleep patterns, they’re still far from substitutes for medical tests utilized in specialized laboratories — and it’s important to keep that in mind when looking at their results.
Sleep measured by sensors
All these tools utilize sensors that compile biometric signals which are combined to determine if we are awake, or in lighter or deeper stages of sleep: accelerometers to detect movements, optical sensors for measuring heart rate, skin temperature or blood oxygen levels, among other metrics.
Smart phones and activity bracelets are currently the most popular sleep monitoring devices. Models from brands like Apple, Fitbit and Samsung automatically record when we sleep, how long we sleep, and how phases of sleep are distributed. In the case of Apple Watch Series 11, for example, every morning users receive a notification summing up how we did the night before, with a score that ranges from 1 to 100. The device tells us things like, “Staying up late tonight affected your score, which ended up at 64.” The app also offers access to data related to breaths per minute, heart rate, vital signs, and statistics organized by week, month or half-year periods. Herein lies the true value of such devices, which allow us to observe trends, detect patterns, and work as tools for awareness and changing habits. By showing data on sleep duration, regularity and interruptions, they can help us to identify problematic behaviors like going to bed too late, using screens before sleep, or slumbering for less than seven hours.
Smart rings: comfort and biometrics
Offerings are similar from smart rings, which are adept at sleep monitoring through their use of sensors that detect heart rate and body temperature variability in a much smaller format than bracelets and watches. Their primary advantage is comfort: many people prefer to sleep wearing a ring, rather than a bulky watch. Their disadvantage is that they also depend on indirect algorithms, which causes them to have the same limitations in precision as other wearables.
One of the models that best illustrates the direction smart rings are moving in is the Circular Ring 2, which features an electrocardiogram sensor — rare among this kind of device — to record the heart’s electrical activity and even detect possible irregularities, like atrial fibrillation. In the area of sleep monitoring, it combines various metrics: it measures heart rate and its variability, skin temperature and blood oxygen levels to estimate sleep phases, recovery and stress level. In addition, it has an accelerometer that detects nighttime movement, key in telling the difference between light, deep and interrupted sleep. One of its key differences lies in its approach to analysis: the app incorporates an AI assistant that translates data into specific recommendations (for example, adjusting schedules or training load based on recovery).
Sleep headphones
As an alternative to traditional earplugs, the Soundcore Sleep A30 are wireless headphones designed specially for sleep. In contrast to conventional earplugs, they incorporate active noise cancellation, designed to reduce nighttime sounds like snoring, traffic and household appliances, and are able to reduce background noise by 30 decibels. Through an app, users can select between music, podcasts or relaxing soundscapes, in addition to white noise or audio with binaural beats designed to facilitate relaxation and sleep.
The headphones also include sleep monitoring functions, with data on duration of rest and sleep position, in addition to personal alarms that only wake up their user. Their battery offers between six to nine hours of playtime, according to the mode being used, which can be extended up to 45 hours with a charging case.
Bedroom sensors
In addition to devices to analyze sleep quality, there are many other gadgets designed for bedtime. One of these, the diminutive Jabees PEACE Pillow Speaker, is designed to listen to audio in bed without using headphones or bothering a bedmate. The device is placed under the mattress or pillow, and transmits sound through bone conduction technology, sending vibrations through one’s pillow to the internal ear, allowing the user to listen to music, podcasts or white noise while keeping ears free.
Meanwhile, Dodow Sleep Aid Device helps to get rest through breathing exercises, projecting a circle of blue light on the ceiling that slowly expands and contracts. The user synchronizes their breathing to its rhythm, encouraging relaxation. Another product, Morphée Sleep Device, comes with dozens of sessions of guided relaxation, meditation, nature sounds and breathing exercises. And Google Nest Hub (second generation) is an intelligent speaker that features a sleep monitoring function via low-energy radar sensors. From one’s bedside table, it can detect movements, breathing, and sleep patterns without requiring the use of worn devices. It also controls lights, plays relaxing sounds and ambient music and can display sleep statistics on its screen.
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