Smartphone Sleep Tracking: A Privacy Concern?

Many people are curious about their sleep patterns and want to track their sleep. There are various ways to do this, including using a wearable device such as an Apple Watch, Fitbit, or Oura Ring, or a phone application such as Sleep Cycle or SleepScore. These applications use different methods to track sleep, including sound-sensing technology, sonar, and movement detection. They can track sleep through blankets and in the presence of another person, as long as the phone is reasonably close by.

Sleep tracking features on smartphones

Sleep tracking has become an increasingly popular feature on smartphones and other devices. Sleep tracking apps are designed to help users understand their sleep patterns and improve their sleep quality. While some sleep trackers are standalone devices that sit on your nightstand or under your mattress, many people opt for sleep tracking apps because they are accessible and relatively inexpensive.

Smartphone sleep tracking apps typically use accelerometer technology or the smartphone's microphone to measure sleep. Some apps, like Sleep.com, use sonar technology to assess both movement and breathing rate, providing an accurate picture of the user's sleep. Sonar technology emits inaudible sound waves from the phone's speakers, which then deflect off the user's chest as it moves while breathing. The phone's microphone picks up on these sound waves, and the app's algorithms use the information to analyze the user's sleep. This technology can even track sleep through blankets.

Another popular option for sleep tracking is to use a wearable device, such as an Apple Watch, Fitbit, or Oura Ring, in conjunction with a smartphone app. These devices use direct skin contact to measure heart rate and motion, providing insights into sleep and wake patterns. The Apple Watch, for example, can measure and track respiratory rate, and this data can be viewed in the Health app on the iPhone. The Oura Ring also provides personalized tips and reminders, such as when to start winding down for bed, to improve sleep quality.

There are also several self-care apps available that offer sleep tracking features, such as Calm and Pillow. Pillow offers a range of extra features, including audio recordings, sleep trends, heart rate and oxygen saturation tracking, sleep sounds, a nap mode, bedtime reminders, and personalized insights. While Calm does not have built-in sleep tracking, it can be used in conjunction with other sleep tracking apps to help users fall asleep.

It is important to note that sleep tracking apps may have limitations and may not provide a perfectly accurate representation of an individual's sleep. However, they can still be useful for understanding sleep trends and making improvements. When choosing a sleep tracking app, it is essential to consider factors such as ease of use, functionality, and the specific features offered.

Sleep tracking wearables

There are several options available for those looking to try a sleep-tracking wearable. The Apple Watch Series 3 and later versions can measure and track your respiratory rate, and this data can be viewed in the Health app on your iPhone or iPad. The Fitbit is another popular option, providing data on sleep stages, blood oxygen saturation, and long-term sleep trends. The Oura Ring is a stylish, sleek option that tracks sleep, stress, activity, heart rate, and more. The ring is designed to be placed on your pointer finger, with sensors at the base of your finger. The Whoop 4.0 is another wristband tracker that provides comprehensive data, although some may find its interface intimidating.

It is important to note that sleep-tracking wearables are not always precise. Many rely on actigraphy, which measures movement, and may assume that a person is sleeping when they are awake but lying still. For medically accurate sleep-tracking data, a polysomnography test is recommended. Additionally, tracking sleep can sometimes increase anxiety about insomnia and do more harm than good.

For those who do not want to wear a device to bed, there are alternative options for tracking sleep. The Sleep.com app uses sonar technology and advanced algorithms to track sleep through the smartphone's speakers and microphone. This app can measure breathing rate, body movement, and sleep patterns without requiring a wearable device.

Sleep tracking apps

SleepScore stands out for its use of sonar technology, which assesses both movement and breathing rate to provide an accurate picture of sleep. It sends silent signals into the user's sleep environment, and its advanced algorithm interprets the reflected sound waves to measure breathing and body movement. SleepScore provides insights in the form of easy-to-understand graphs and scores, making it ideal for users who want to track their sleep progress.

Sleep Cycle is another comprehensive sleep tracking app that utilizes the phone's sound recorder to analyze sounds and track sleep. It offers detailed stats, sleep graphs, and smart alarms to enhance the user's sleep experience. However, some of its features require a premium subscription, and it may be overwhelming for those seeking a simpler solution.

The Apple Sleep app, available on Apple Watch Series 3 or later with watchOS 8, integrates with the Health app on iPhones. It can measure respiratory rate and track sleep when the user wears the Apple Watch to bed. The Health app also allows users to set sleep goals, create a customized sleep schedule, and reduce distractions before bedtime.

While these sleep tracking apps offer valuable insights, it is important to note that they may not always accurately distinguish between sleep and wakefulness. They can be affected by external factors, such as the user's movements or the presence of a bed partner. For more serious sleep concerns, consulting a doctor or seeking professional sleep evaluation is recommended.

Sleep tracking accuracy

Sleep tracking devices have become increasingly popular, with one source estimating that one in three Americans have used a sleep-tracking device. These devices are convenient and cost-effective tools for monitoring individual sleep habits and can be used to set sleep goals and create a customised sleep schedule. They can also be used to track sleep duration, quality, and phases. However, it is important to note that sleep tracking devices do not directly measure sleep. Instead, they often rely on measuring inactivity as a surrogate for estimating sleep.

There are several types of sleep trackers available, including below-mattress sensors, wearables, and smartphone apps. Wearables, such as those made by Fitbit, Whoop, Apple, and Oura, use direct skin contact to measure heart rate and motion to determine sleep and wake patterns. Wearables have been found to be as accurate as, or even better than, actigraphy, a sleep test based on data collected from a wrist-worn device that is typically only available from a medical professional or through a lab-based study. However, a 2024 review found that the accuracy of consumer sleep trackers compared to actigraphy means wearers can expect data that is on par with some research-grade sleep-tracking devices.

Smartphone apps, such as the Sleep.com app, use sonar technology to assess movement and breathing rate to provide an accurate picture of an individual's sleep. The Sleep.com app has been found to be accurate in tracking sleep even when the user is sleeping with a partner or under blankets. However, it is important to note that the use of a fan or speaker at night may interfere with the app's tracking accuracy if the devices are not positioned at least six feet from the phone.

While sleep trackers can provide a wealth of information about an individual's sleep habits, it is important to take the data with a grain of salt. For exact data about sleep habits, a medical sleep study that monitors brain waves is necessary. Additionally, more research is needed to verify the reliability of sleep trackers, especially as the technology continues to evolve.

Sleep tracking with Apple Watch

Sleep tracking is available on watchOS 8 or later. To track your sleep using an Apple Watch, you must first enable sleep tracking. To do this, open the Health app on your iPhone and tap 'Get Started' under 'Set Up Sleep'. Then, tap 'Next'. From here, you can set a sleep goal, bedtime and wake-up times, and Sleep Focus to reduce distractions.

Once you have set up sleep tracking, you must ensure your Apple Watch is charged to at least 30% before you go to bed. When you wear your Apple Watch to bed, it will automatically measure and record the number of times you breathe in a minute. It will also track your sleep and add sleep data to the Health app on your iPhone. To view your sleep history, open the Health app on your iPhone or iPad and tap 'Browse' at the bottom of the screen.

If you want your Apple Watch to remind you to charge it before your wind-down time, you can turn on Charging Reminders. You can also view your recent sleep data on your Apple Watch by opening the Sleep app and turning the Digital Crown. This will allow you to view your Sleep Stages data, Time Asleep, and Sleep Duration for the last 14 days.

Frequently asked questions