Many commercial sleep tracking devices are available to meet various consumer preferences. Consumers may choose wearable and contact-free accelerometers that sense and measure movements to predict sleep and wake periods (3). Although companies do not make device algorithms publicly available, many claim to be able to calculate light sleep, deep sleep, rapid eye movement (REM) sleep, and wake on the basis of movement alone (4).

Popular wearable sleep trackers include wrist-based devices such as Fitbit and finger-based devices like Thim. The wrist-based devices require a consumer to wear the device like a watch throughout the day and night and predict sleep time through the presence or absence of movement. According to its web site, Fitbit intends to improve sleep habits through tracking and recording sleep duration, light sleep/deep sleep/REM sleep, sleep schedule, heart rate, and movement. It also provides comparative “sleep insight” on the basis of consumer data, gender, and age (5). Consumers are then able to access and review nightly data through a mobile phone or tablet app and online software. Comparatively, the finger cup, Thim, is another wearable option and requires users to wear a “smart ring” at night to track movements and predict sleep. Instead of improving sleep habits through data monitoring, Thim claims to improve sleep quality through sleep training (6). During the first hour of sleep, the finger cup vibrates and interrupts sleep in 3-minute intervals in an attempt to condition the wearer to sleep better the remainder of the night. The cup then records finger movements and uses an algorithm to predict sleep stages (6). Like the wrist-based devices, recorded data can be viewed on a smartphone or tablet app to track sleep efficiency (SE).

Consumers who do not wish to wear devices during the day or while in bed may opt to utilize contact-free devices to track their sleep. While also utilizing accelerometers to record movements and algorithms that estimate sleep stages and wake on the basis of the amount of movement, contact-free devices present a sleep tracking option on the basis of comfort. Several sleep tracking apps are available to download onto the user’s smart-phone or tablet from mobile app stores. Many sleep tracking apps offer a basic version for free with in-app optional purchases for more advanced versions with additional tracking features. Some contact-free devices may be used in conjunction with wearable devices but can function independently as well, offering consumers a low-cost option to monitor sleep.

Because sleep tracking apps rely on accelerometers to predict sleep, the recording device must be in close proximity to the user to sense and record movements. The Pillow app recommends that users position the device facedown on either the mattress or pillow about 15 to 25 cm from their bodies (7). In addition to an accelerometer, the Pillow app also utilizes audio input from nightly recordings in their algorithm to estimate sleep stages and quality (7). Users can access their nightly sleep report through the app and may opt to purchase app upgrades to access additional sleep statistics and tracking resources.

The wide accessibility and convenience of commercial sleep technology has increased the ease and popularity of monitoring personal sleep health. Apple watch Sleep Watch app and Jawbone UP app are both examples of commercial wearable devices that provide a daily sleep chart of the user. Information is displayed in easily interpreted charts and graphs (8). The data are recorded and can be viewed anytime through the associated app or web site. This method of collecting and monitoring personal health data can be fun and enlightening and gives users objective information about their personal rest and bedtime and wake patterns (3). Being personally involved in their own sleep health and analyzing their own sleep trends could motivate users to make changes and thus improve sleep hygiene and habits. They may further seek information on sleep disorders and/or medical treatment for consistently negative or concerning reports. Readily available sleep data empower the public to be engaged in, and knowledgeable about, their sleep health.

However, commercial sleep technology has limitations. Despite continuous technologic advances and product upgrades, technology is prone to inaccuracies and technical failures, which can result in misleading data. Polysomnography (PSG) is considered the gold standard in evaluating sleep quality because it measures brain activity, muscle tone, and eye movements, which are necessary to distinguish sleep stages (3). Movement and noise may be able to suggest periods of wake versus sleep, but they are not strong sleep stage indicators because there is little variation in the amount of movement between sleep stages (3). Additionally, the accelerometer and audio recorders in sleep tracking devices could detect and record sounds and movements from another person or pet sharing the bed and skew the user’s sleep report: detecting outside movements could overestimate restlessness and periods of wake, or inversely, depending on the user’s ability to lay still, misinterpret periods of motionless wake as sleep and overestimate sleep time (4). Misrepresenting sleep quality could lead to a false sense of security or concern, either of which could negatively impact health. Furthermore, multiple research studies evaluating commercial sleep technology accuracy have had to exclude participant data because of device malfunctions and user error in both wearable and contact-free devices (4, 8). Because of potential inaccuracies, data collected from commercial sleep trackers should be interpreted with caution.