Personal Health Monitors: Tracking Your Rem Sleep

Sleep trackers are devices that monitor your sleep, providing insights into the quantity and quality of your sleep. They can help identify sleep problems and track your progress as you implement strategies to improve your sleep. While they are not perfectly accurate, they can be a useful tool for optimising your sleep.

There are a variety of sleep trackers available, including smartwatches, rings, and sensors that go under your mattress. Some popular options include the Oura Ring, Whoop 4.0, and Apple Watch. These devices can measure heart rate, skin temperature, and time spent in different sleep phases, such as REM, light sleep, and deep sleep. They provide data and analytics through companion apps, offering insights and recommendations to improve your sleep.

When choosing a sleep tracker, consider factors such as comfort, additional features, subscription requirements, price, and user reviews. It is also important to remember that sleep tracking may not be suitable for everyone, as it can increase anxiety for some individuals.

Wearable sleep trackers

Some popular options for wearable sleep trackers include:

• Oura Ring 4: This ring offers insights into sleep efficiency, restfulness, readiness, and latency. It tracks sleep cycles, total sleep time, resting heart rate, heart rate variability, and movement. It has a comfortable, lightweight fit, impressive battery life, and a discreet build. However, it requires a paid membership to unlock all features.
• Apple Watch Series 10: This smartwatch is a good option for Apple users. It offers sleep cycle tracking, sleep apnea detection, and a larger, thinner, and brighter display compared to its predecessor. However, it does not provide a sleep score or summary.
• Google Pixel Watch 2: This smartwatch is a great choice for Android users. It integrates Fitbit's sleep tracking technology, offering nightly trends, a silent alarm, bedtime reminders, and sleep goals. It is lightweight and comfortable for sleep. While it has a shorter battery life, it charges quickly.
• Garmin Venu 3S: This smartwatch is ideal for athletes and fitness enthusiasts. It provides a sleep score, tracks sleep stages and naps, and monitors heart rate variability and skin temperature. It has a long battery life but sleep tracking can drain the battery.
• Whoop 4.0: This is a lightweight, screenless band that tracks sleep stages and suggests optimal sleep times. It has a personalized sleep coach feature and provides detailed sleep trends. It requires an annual membership subscription.

While wearable sleep trackers can be a helpful tool, it is important to note that they are not perfectly accurate and should not replace medical advice. They can provide insights into your sleep habits and help you make adjustments, but for exact data and diagnosis of sleep disorders, a medical sleep study is necessary.

Non-wearable sleep trackers

There are a variety of non-wearable sleep trackers available on the market. These include:

Withings Sleep Tracking Mat

This thin mat is placed underneath your mattress and uses pneumatic and sound sensors to measure your heart rate, respiratory rate, movements, snoring and sleep cycles. It automatically compiles your data into a sleep diary and can also turn off the lights when you get into bed. However, it may record periods of wakefulness as light sleep and requires an outlet nearby to plug in.

Withings Sleep

Withings Sleep is a non-wearable sleep tracker that slides under your mattress to collect data on your sleep cycle, heart rate, movement, breathing and snoring. It can sync with smart home devices to coordinate light levels and room temperature based on whether you are awake or asleep. However, it is not compatible with mattresses that are more than 15 inches thick.

Eight Sleep Pod 4 Cover

The Eight Sleep Pod 4 Cover is a mattress cover that fits over a bed like a fitted sheet and contains a system of wires that pump water throughout the cover to heat and cool sleepers. It has sensors to track temperature (ambient and body), heart rate, heart rate variability, respiratory rate, movement, and sleep stages. It gives you a sleep score out of 100 each morning and offers charts and advice to help you improve your sleep. However, it is very expensive and requires a subscription to access sleep tracking.

Asleep SleepRoutine App

SleepRoutine is a sleep-tracking app that provides a report for each night, breaking your sleep into awake, light, deep and REM phases. It also allows you to add notes to help it better understand your sleep and has a smart alarm function. However, the app can be a bit unreliable, sometimes failing to produce a report in the morning with no explanation.

Google Nest Hub 2nd Gen

The Google Nest Hub 2 uses radar to track your sleep and also has a microphone to monitor snoring, sleep talking and other nocturnal sounds. However, it consistently overestimated REM sleep and missed periods of wakefulness in testing.

Sleep tracker accuracy

Sleep trackers are becoming increasingly popular, with many people wanting to gain insight into their sleep patterns and improve their sleep quality. While these devices can be useful, it's important to understand their limitations and potential inaccuracies.

Sleep trackers use a variety of methods to monitor sleep. Most wearable trackers, such as wristbands or rings, measure body movements and sometimes heart rate data to estimate sleep patterns. Some trackers also take into account environmental factors like light or temperature in the bedroom. There are also non-wearable trackers that can be placed on the bedside table or under the mattress. These devices often rely on measuring inactivity as a surrogate for estimating sleep.

Accuracy of Sleep Trackers

The accuracy of sleep trackers has been the subject of limited research. Compared to polysomnography tests, which are used by experts to diagnose sleep disorders, sleep trackers have an accuracy of about 78% in identifying sleep versus wakefulness. However, this accuracy drops to around 38% when estimating how long it takes for an individual to fall asleep. Polysomnography tests are considered the gold standard as they track brain waves, heart rate, breathing, blood oxygen levels, and body and eye movements during sleep.

Sleep trackers that only measure body movement may struggle to differentiate between sleep stages, as movement occurs during all stages of sleep. Additionally, the algorithms used by companies to make predictions about sleep are often unknown, making it challenging for scientists to validate the assumptions made by these devices.

Trackers that incorporate heart rate data tend to be slightly more accurate, especially when measuring sleep duration, as heart rate fluctuates during different sleep stages. However, even these devices may underestimate or overestimate the amount of deep sleep obtained.

It is important to note that the accuracy of sleep trackers can vary depending on the individual. For example, people with insomnia tend to remain very still while trying to fall asleep, which can make it difficult for movement-based trackers to differentiate between sleep and wakefulness.

Factors Affecting Sleep Tracker Accuracy

• Type of Tracker: Wearable trackers that measure heart rate and other physiological parameters tend to be more accurate than those that solely rely on movement.
• Comparison to Gold Standard: Polysomnography tests, which monitor brain waves and various physiological parameters, are considered the most accurate way to study sleep.
• Individual Variations: Certain conditions, such as insomnia, can affect the accuracy of sleep trackers, especially those that rely on movement detection.
• Algorithm Variability: The algorithms used by different companies may vary, and the lack of transparency makes it challenging to assess their accuracy fully.

While sleep trackers can provide valuable insights into sleep patterns, they should not be solely relied upon for diagnosing or treating sleep disorders. It is important to consider their limitations and potential inaccuracies. If you have concerns about your sleep, it is always best to consult a healthcare professional, who can advise you based on your individual needs and circumstances.

Sleep tracker data

Sleep trackers can also provide meaningful data on the quantity and quality of your sleep on a nightly basis. They can help identify sleep problems and track your progress as you try out different strategies.

Sleep trackers can monitor:

• Sleep duration
• Sleep quality
• Sleep phases
• Environmental factors, such as light and temperature
• Lifestyle factors, such as caffeine consumption and stress levels

Sleep trackers can be a wearable device, like a bracelet or ring, or non-wearable sensors that sit on your bedside table or under your mattress.

While sleep trackers can be a helpful learning tool, they don't replace medical care. If you have insomnia, sleep apnea, orthosomnia, or any other kind of sleep-related disorder, see a medical professional.

Here's a closer look at the data provided by some of the best sleep trackers on the market:

Oura Ring 4

The Oura Ring 4 is a stylish, lightweight, and comfortable ring that monitors an array of metrics, including sleep and daily activity. It measures your heart rate, temperature trends, and blood oxygen levels throughout the day and night. It then translates this data into three scores: Sleep Score, Activity Score, and Readiness Score. The Oura Ring 4 also serves as a fitness tracker and provides tips to optimize your health.

WHOOP 4.0

The WHOOP 4.0 is a lightweight, compact, and versatile sleep tracker. It can be worn as a wristband or used with different garments such as sports bras, leggings, and boxers. It helps optimize sleep by monitoring your heart rate, respiratory rate, blood oxygen levels, and skin temperature. It also features a smart alarm designed to prevent grogginess by gently waking you up during the ideal moment in your sleep cycle.

Rise Science Sleep Tracker

The Rise Science Sleep Tracker is an app that can be used on its own or with wearable devices. It connects with health apps on your phone to track your sleep debt and circadian rhythm to help optimize your sleep duration. It integrates various sources of data to identify when you're not getting enough sleep and suggests ways to enhance your sleep habits.

Sleepon Go2Sleep 3 Tracker

The Sleepon Go2Sleep 3 Tracker is a silicone ring that syncs with your phone and can identify dips in blood oxygen levels, which may help detect underlying sleep-related breathing disorders. It also monitors blood glucose levels, heart rate, and sleep stages. It provides alerts if your blood oxygen level drops too much.

Bía Smart Sleep Mask

The Bía Smart Sleep Mask is a multipurpose sleep tracker that uses advanced technology to monitor brain activity and track your sleep stages. It also blocks out external light, offers a simulated sunrise wake-up function, and plays relaxing music to help you fall asleep.

Withings Sleep

The Withings Sleep is a non-wearable sleep tracker that slides under your mattress to collect data on your heart rate, movement, breathing, and snoring. It can sync with smart home devices to coordinate light levels and room temperature based on whether you're asleep or awake.

Fitbit Inspire 3

The Fitbit Inspire 3 is a sleek, affordable, and user-friendly sleep tracker. It measures heart rate, blood oxygen levels, time spent in different sleep stages, and overall sleep quality. During the day, it can track steps, workouts, calories burned, and more.

Garmin Forerunner 165

The Garmin Forerunner 165 is ideal for runners who want GPS to track their runs and insights into their sleep and recovery. It features Sleep Coach, sleep score, and nap detection, tracking sleep cycles, duration, HRV, restless moments, resting heart rate, and respiration rates.

Withings ScanWatch 2

The Withings ScanWatch 2 is a high-quality sleep tracker with a sleek, traditional watch design. It measures HRV, heart rate, AFib detection, respiratory rate, breathing disturbances, blood oxygen, temperature, snoring, activity, menstrual cycle, and sleep quality.

Eight Sleep Pod 3 Cover

The Eight Sleep Pod 3 Cover is a luxury mattress cover that fits over a bed like a fitted sheet. It contains a system of wires that pumps water throughout the cover to heat and cool sleepers, mimicking the body's natural temperature cycles during sleep. It also measures sleep stages, overall sleep quality, heart rate, HRV, breathing rate, and snoring.

Withings Sleep Tracking Mat

The Withings Sleep Tracking Mat is a thin mat that goes under your mattress to track your heart rate, respiratory rate, movements, snoring, and sleep cycles. It automatically compiles your data into a sleep diary in the Withings app.

Sleep tracker features

Sleep trackers can be a great way to monitor your sleep and gain insights into your sleep patterns and quality. They can help you identify sleep problems and track your progress as you work towards improving your sleep habits. Here are some features to look out for when choosing a sleep tracker:

Wearables vs Non-wearables

Sleep trackers come in two main forms: wearables and non-wearables. Wearable sleep trackers are devices that you wear on your body, such as rings, wristbands, headbands, or smartwatches. They tend to be lightweight and can collect health data throughout the day, in addition to sleep tracking. Some people may find them uncomfortable to sleep in, especially bulkier options like smartwatches. Non-wearable sleep trackers, on the other hand, are devices that you don't need to wear on your body. They can be placed on your bedside table, clipped to your pillow, or placed under your mattress. These options are ideal for those who find wearables uncomfortable or prefer a more discreet tracking method.

Sleep Duration Tracking

A basic feature of sleep trackers is the ability to track sleep duration. They do this by monitoring periods of inactivity, detecting when you fall asleep and when you wake up. This information can help you understand if you're getting enough sleep and identify any patterns related to your sleep duration.

Sleep Quality Analysis

Sleep trackers can also provide insights into your sleep quality. They detect interruptions during your sleep, such as tossing and turning or waking up multiple times during the night. Additionally, some trackers use algorithms to analyse your sleep stages and provide an overall sleep score, giving you a clearer picture of your sleep quality.

Sleep Phase Tracking

Some sleep trackers go beyond just tracking sleep duration and quality by monitoring the different phases of sleep. They can track light sleep, deep sleep, and REM sleep, helping you understand the composition of your sleep. Some advanced trackers even use this information to optimise your alarm, waking you up during a lighter sleep phase to make it easier for you to get up.

Environmental and Lifestyle Factors

Certain sleep trackers also take into account environmental and lifestyle factors that can impact your sleep. They may record factors like the amount of light or temperature in your bedroom. Some trackers also prompt you to input information about your daily activities, such as caffeine intake, meal times, or stress levels, to help identify how these factors influence your sleep.

Smart Features

Many modern sleep trackers offer smart features that enhance their functionality. For example, some trackers have smart alarms that gently wake you up during an optimal moment in your sleep cycle. Some trackers can also integrate with smart home devices to adjust lighting and temperature based on whether you're asleep or awake. Additionally, some trackers provide health coaching and motivational features to help improve your sleep habits.

Compatibility and Convenience

When choosing a sleep tracker, it's essential to consider compatibility with your other devices. Ensure that the tracker and its companion app are compatible with your smartphone or computer. Also, consider the convenience factors, such as battery life and charging methods. Look for options with longer battery life and convenient charging options to avoid the hassle of frequent charging.

Accuracy and Data Insights

The accuracy of sleep trackers is an important consideration. While no consumer device can match the accuracy of a medical sleep study, trackers that monitor heart rate and blood oxygen levels tend to provide more reliable data. Additionally, look for options that provide detailed data insights and visual representations, such as graphs or reports, to help you easily spot trends in your sleep patterns.

Frequently asked questions