Sleep trackers use your heart rate and movement to evaluate the efficiency of your rest, help you establish a healthy sleep routine and allow you to analyse those horrible nights spent tossing and turning.
It’s important to prioritise sleep – regular poor sleep can have negative impacts on everything from cognitive function and blood pressure, to immune health and inflammation.
If you don’t want to wear a sleep tracker, which you usually strap to your wrist, then there are non-wearable devices that slide under your mattress and communicate your sleep data via your WiFi.
All devices are usually supported by an app, which gives a daily breakdown of how you slept, often alongside other insights such as fitness activity, stress levels and SpO2, also known as pulse oximetry, which measures oxygen saturation in your blood and can detect sleep apnea.
Read on to discover our pick of the best sleep trackers and don’t forget to scroll down to our detailed buyer’s advice section to research further before you invest.
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The best sleep trackers at a glance
- Best budget sleep tracker: Xiaomi Mi Band 5, £39.99
- Best high-end sleep tracker: Apple Watch Series 6, from £379
- Best all-in-one sleep tracker: Garmin Venu Sq, from £179.99
- Best for ease of use: Whoop, from £30 (subscription)
- Best for sleep apnoea: Withings Sleep Analyzer, £99.95
- Best wearable tracker for fitness fans: Polar Unite, £134.50
- Best non-wearable tracker for fitness fans: Emfit QS Active, €299.98
- Best for sleep and stress tracking: Fitbit Sense, £299.99
- Best discreet sleep tracker: Oura Ring, $299
The best sleep trackers to buy online
Xiaomi Mi Band 5
- Available from Amazon (£39.99)
Best budget sleep tracker
For this price we thought it impossible to find a reliable, durable sleep tracker, but we were proven wrong when we tested the Mi Band 5.
You don’t get a breadth of intuitive functions and display options here, but you do get sleep tracking, heart rate monitoring and GPS activity tracking (when paired with your phone).
The sleep tracking – which offers a sleep score, measures cycles, disturbances and efficiency – easily holds it own against rival, more expensive trackers. And the device’s app is easy to follow and it’s possible to isolate specific intel, plus you can integrate Apple Health or Google Fit into it.
The touchscreen is responsive and easy to read, the device is water and swim proof, and the battery life is up to 14 days. The downsides are fair for under £40: only 11 sport modes, no wallet app and no inbuilt GPS, so you will always have to take your phone with you when you work out.
Available from Amazon (£39.99)
Apple Watch Series 6
Best high-end sleep tracker
You will pay top dollar for Apple’s latest watch (£379 is a starting price), but if you want every function, metric and app, plus beautiful and intuitive design, then the Series 6 is your only choice. Most importantly (for our testing purposes) it contains sleep tracking.
Rather than a nerdy data-driven experience, the Series 6 pushes you to create a healthy sleep routine. To get the best of it, you need to follow its advice. Set a bedtime and sleep time, embrace the nightly Wind Down function, make the most of the mindfulness and breathing apps and use the data generated from your rest to improve your daily sleep schedule rather than a stick to beat yourself with.
There are a lot of bells and whistles: an SpO2 sensor, a hand-washing feature, music apps, Alexa, excellent GPS fitness tracking and an ECG app to record your heartbeat. It’s hard to have such data whizzing around on your wrist and not look at it constantly – especially when all your calls, messages and social media is feeding into it – but we played around with the settings and after a few days, felt we had the right mix of information and peace.
Battery life is 36 hours at best so you’ll need to find 83 minutes to charge it every day or so.
Garmin Venu Sq
Best all-in-one sleep tracker
The Venu Sq packs in a lot of functions with only two buttons and a touch screen to navigate. It’s not a watch for sausage fingers, but it is a brilliantly reliable all rounder that ticks several important boxes.
Sleep tracking is done in the background and must be viewed on the free Garmin Connect app, which could be seen as a downside but since the sleep data is so detailed, we preferred looking at it on an app.
The app reviews sleep stages with a clear graph and stats, which we found accurate, alongside pulse ox analysis and respiration (the latter on-point, the former hard to verify).
There’s a one-day and seven-day sleep review but note the sleep tracking doesn’t work for naps.
On top of this, it has a stress tracking function, which is complemented by breath work and mindfulness functions – we utilised them in the evening as part of our sleep routine. There’s also menstrual tracking and accurate GPS fitness tracking for most sports (it’s waterproof up to 50 metres).
Standby battery life is a decent six days, the strap is simple to adjust (something frustratingly rare in sleep trackers) and there’s also a music-enabled option for £229.99.
- Available from Whoop (join from £30)
Best for ease of use
If you’re only interested in sleep data then you need Whoop, a wrist strap so discreet and comfortable you’ll forget you have it on.
The purchase model is different to other trackers: select a strap (black is included in your subscription, or there are 11 other colours that start at £25 each) and choose from one of three payment plans (from £18 a month).
There’s no screen on a Whoop, instead analytics are viewed on its app, which might frustrate some but we enjoyed one less distraction in our data saturated lives.
The app collates expected data: heart rate, calorie burn, hours slept, sleep stages, disturbances and respiratory rate. It also uses algorithms to generate scores for ‘strain’ (how far you’ve pushed your body) and ‘recovery’ (how rested your body is).
It also measures heart rate variability (HRV) – the variance in time between the beats of your heart. Studies show the greater HRV, the more able your body is to perform at more strenuous levels.
These metrics are Whoop’s USP. It’s an incentive to look after yourself, but also to push yourself when your watch says you can. The device has a five-day battery life and is charged by a USB battery pack. The only negative? The fabric strap needs replacing every few months.
Available from Whoop (join from £30)
Withings Sleep Analyzer
Best for sleep apnoea
This thin mat, which slips under your mattress, is the best way to check for sleep apnoea, a disorder that causes a person’s breathing to be interrupted during sleep and can cause extreme fatigue and headaches, and can lead to high blood pressure and a higher chance of stroke.
You will need one mat per person and a plug socket within three metres of the bed to power it. Data is sent to Withings’ app, Health Mate, which presents the mat’s insights – including snore detection thanks to a small mic in the mat – in a helpful traffic light design. iPhone users can add their Apple Health data to incorporate daily steps and workouts.
We found the sleep data accurate – particularly the nighttime wakings – and the daily sleep score usually matched how we ‘felt’ we’d slept.
The stand out feature is its ability to detect signs of sleep apnea and while that function is awaiting FDA approval in the US, in a clinical trial, the Analyzer was shown to achieve similar results to polysomnography, a diagnostic test usually performed in sleep labs.
Results are presented on a scale (mild, moderate, severe) with explanations of each, surveys to take and advice on when to see a doctor. It won’t replace a professional diagnosis but based on the research and our own results, it’s a reliable indicator of a potential problem.
Polar Unite Fitness Watch
Best wearable sleep tracker for fitness fans
Endorsed by a long list of professional runners and triathletes, Polar Unite’s expertise lies in providing accurate insights on a range of activities and metrics, plus reliable evaluation of how you perform when you aren’t active.
All the standard issue sleep analysis is present – sleep time, actual sleep percentage, disturbances, sleep cycles and sleep continuity – but it’s the measure of your autonomic nervous system recovery that sets it apart from other trackers.
Your autonomic nervous systems activates in stressful situations – including workouts – but should stabilise. If it doesn’t – because you’re anxious or intoxicated, for example – that will affect your body’s ability to recover and perform. Unite reflects this in its Nightly Recharge score, which is available to view on the mostly touchscreen watch or in Polar’s Flow app.
Fitness-wise, the device can track, and offer feedback on, 100 activities and features. The stand out is the FitSpark function, which recommends workouts to help improve your personal fitness levels.
Add to that waterproofing up to 30 metres and an elegant watch face, and you have a reliable, accurate, wearable device all at a price much lower than competitors. The only negative is the GPS, which isn’t in-built and must be paired with a phone.
Emfit QS Active
- Available from Emfit (€299.98)
Best non-wearable sleep tracker for fitness fans
Emfit QS Active isn’t for tracking the minutiae of every physical exertion. Instead, it gathers your nighttime data (heart rate, cycles, respiratory rate, disturbances), and informs you of your sleep quality and recovery state, which can then be used to formulate training plans and rest days.
Like Whoop, heart rate variability is a key component here – the higher your HRV, the more ready you are to push yourself. And like Polar’s Unite, it also assesses your autonomic nervous system to gauge your recovery state. It’s a reliable, fuss-free way to measure your body’s ability to cope with strain.
The device is a thin belt-like sensor that sits under your mattress, with a two-metre long cable for plugging it in. Data is viewed on a desktop app, which is easy to follow despite the scientific UX, and you can drill down on individual stats to gain more granular insights.
Helpfully, information can be exported via CSV format, allowing you to share it with a fitness buddy or trainer. One bug bear is the multi-stage set up, which will only be successful if you are connected to your Wifi’s 2.4 GHz, rather than the standard 5GHz.
Available from Emfit (€299.98)
Best for sleep and stress-tracking
Sleep and stress go hand in hand, or rather they don’t, which is where Fitbit’s Sense comes to the rescue.
The smartwatch features the same spot-on sleep tracking tech that all its models do, but also offers daily stress-tracking and the world’s first electrodermal activity (EDA) sensor. Using EDA responses, detected via the conductivity of your skin, the device can measure your stress levels.
The EDA scan doesn’t run in the background – you need to sit still for two minutes while it works its magic – but it’s worthwhile for the results, which we found spot on, and the mindfulness exercises were beneficial on high-stress days; we particularly liked using them before bedtime.
Speaking of which, Fitbit’s sleep tracking is impressive, with data on your baseline temperature, SpO2 tracker to help spot sleep apnea and a thorough breakdown of your sleep cycles, efficiency, disturbances and so on. However, you will need a premium subscription to get a full breakdown (currently free for a 90 day trial).
The smartwatch comes with several apps as standard, including wallet, Alexa and Spotify, plus a host of other paid-for apps that can be added. Battery life is six days (providing you don’t turn on GPS for long).
- Available from Oura ($299)
Best discrete sleep tracker
Prince Harry and Twitter CEO Jack Dorsey are reportedly fans of Oura, a minimalist tracker ring, which comes in two styles and up to four finishes, and packs a lot into such a tiny accessory.
You will first need to measure your finger via a postal kit, and then order your ring. The exterior looks like a chunky ring, but the inside contains infrared LED sensors, two body temperature sensors, a 3D accelerometer, and a gyroscope.
Your data pops up on Oura’s stylish app, an impressively comprehensive combination of data. Sleep duration, efficiency, cycles and latency are all present, but so too are heart rate, heart rate variability, body temperature, respiratory rate and training frequency.
On top of that, the app features advice on sleep hygiene and audio stories, which act like guided meditation, and are designed to help you relax and fall asleep. The sleek design and holistic approach means Oura doesn’t feel like a tracker, rather a self care tool.
Our only niggle is the charger cradle, which the ring sits on top of – but isn’t locked in. It’s fine for charging at home, but if you’re on the go – or have small children around who pick up everything – we can imagine the ring getting misplaced quickly.
Available from Oura ($299)
Sleep tracker buyer’s advice guide
What is a sleep tracker?
Sleep trackers monitor your heart rate and movement, interpret the data and display the results on an app on your phone or desktop, and in some cases show the data immediately on the device screen. They are mostly worn on the wrist but there are non-wearable devices, usually in the form of a thin sensor, which is mains-powdered and sits under a mattress.
How do they work?
By tracking heart rate and movement, they can detect your sleep cycles, how often you wake up, how long you were awake for and how long it takes you to fall asleep (known as latency).
A person’s sleep cycles between non-rapid eye movement sleep (which has three stages: light, slow wave brain activity and deep sleep) and rapid eye movement sleep (where you dream). A sleep tracker will evaluate each night’s sleep, breaking it down into easy-to-understand graphs and percentages, often marking you an overall score for your night’s rest.
The higher your sleep efficiency (what percentage of your time in bed you were actually asleep) the better your quality of rest. For the best results, wearables should be worn all the time (most are waterproof).
Some sleep trackers measure only that; others track several activities, including fitness, stress levels and Sp02 levels, which can detect sleep apnea. There are also sleep trackers that can be synced with your smartphone to mirror your message, calls, photos and music apps.
How accurate is a sleep tracker?
For true accuracy you would need to be hooked up to an electroencephalograph to measure your brainwaves – but sleep trackers are the most accurate way of assessing your sleep efficiency and cycles without sleeping in a lab.
There is also the function to edit data, so you can update your nightly results to help improve the accuracy, and import data from other health and fitness apps. Sleep trackers alone aren’t the golden pill for sleep health – they should be used in conjunction with good sleep hygiene.
For some people, sleep trackers can add to their anxiety over sleep – or lack of it. If you suffer from orthosomnia – a sleep disorder where a patient becomes preoccupied by their sleep efficiency – then you should try a more intuitive sleep approach, and consider seeking professional help. Head here for more tips on how to get a good night’s sleep.
How should I choose a sleep tracker?
Which device is right for you depends on how you want to track your sleep (on your body or in your room) and what data you want to collect (sleep, fitness, stress levels and so on).
There are devices that will only track sleep, but if you also want to listen to music, field messages and track your fitness, then you would be wise to consolidated it all into one device.
You should also consider style, materials and ease of use. Usually, the bigger the range of functions, the higher the price, ranging from £40-£400 depending on the spec.
How to set up a sleep tracker
Most devices have a straightforward set up. Wearables usually need a period of charging, and then they can be switched on and paired with your phone, often through a free app from the manufacturer.
You can then review and edit your data at any point. With non wearables, the set up can be more complicated, as it involves connecting with your home WiFi, which you will need to be strong in the room you are sleeping in (a Wifi booster can help with this).
All the devices we tested came with printed instructions, and we found YouTube tutorials on set up and usage for many of them. Running an app constantly in the background of your phone will drain your battery quicker, but it will allow your data to be processed immediately.
What we looked for when testing
Every device featured was tested for 24 hours a day for a minimum four-day period (often longer).
We assessed the sleep tracking functions, battery life, fit, set up, design, and additional functions, such as music, activity tracking and messaging.
Finally, we considered the type of person best suited to each device – if you only want to evaluate your sleep, there’s not much point in having a watch that can measure your mile pace or swimming speed. If you’re an athlete, on the other hand, those features will be essential.
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This review was last updated in January 2021. If you have any questions, suggestions for future reviews or spot anything that has changed in price or availability, please get in touch at email@example.com.