Overview
It is recommended that the average adult sleep between 7-9 hours. However, approximately 1 in 3 adults are reporting sleeping less than 7 hours a night. An additional 50-70 million Americans suffer from chronic sleep disorders. Although seemingly common, continuous poor sleep is associated with risk of cardiovascular disease, psychological disorders, obesity, diabetes, weight gain, and cognitive performance and more.¹ Sleep tracking devices such as wearables, non-wearables, and stand alone apps have become increasingly popular methods of managing sleep. However, most sleep tracking methods are not FDA approved and there is limited research regarding their accuracy. In this article I will provide an overview of various sleep tracking devices so that students can be better informed about the nature of said products.
What is a Sleep Tracker?
Sleep trackers are devices that monitor aspects of your sleep in order to examine different sleep trends such as stages, habits, quality, and duration. The majority of trackers analyze respiration and heart rate, which are known to be associated with stages of sleep. Some detect movement to examine quality or record sounds, which can be useful when assessing sleep apnea. Others use microphones to pick up on movement and ambient noise. Occasionally, trackers contain thermometers to gauge how room temperature may be influencing sleep quality. The majority of wearables and non wearables can pair with phone apps to present personal data in a more accessible manner. Sleep apps often include other fitness tracking features such as a step count.²
Wearables, Non Wearables, and Stand-Alone Apps
Although wearable and non wearable sleep trackers record similar kinds of data, they use different methods of acquiring it. Wearable devices are worn on the body, usually in the form of watches or wristbands but also existing as rings, headbands, or eye masks. Alternatively, non-wearables sit under or on top of your mattress and work to monitor vibrations during sleep. Non wearables are typically thin enough to be undetectable, but some sensitive sleepers may be able to notice a difference. Stand alone apps can work with or without wearable or non wearable devices. If you don’t have access to another sleep tracker, apps will often use information from apple health or another comparable phone app.³
Why Use Sleep Trackers?
Many people have difficulty regulating sleep on their own. You may experience difficulty heading to bed at an appropriate time, or waking up at a time that is best suited to you. Many sleep trackers contain a smart alarm, which allows you to set a designated window of time for you to wake up. Because it is easier to wake during light sleep but harder in deep sleep, trackers can assess whether you are sleeping lightly and trigger a morning alarm to wake you at the right moment. Sleep tracking devices can help you learn more about when you wake up and fall asleep, how and when you accumulate sleep debt, and can provide tools to help diagnose a potential sleep disorder. If you are feeling fatigued during the day, or are having trouble falling asleep at night, try tracking your sleep for a few weeks to see if any patterns arise. You can then discuss the information with your doctor who will help you come up with a long term plan.
Accuracy of Sleep Trackers
When using stand alone sleep apps it is important that you make sure the information on your app is correct: this means checking apple health or whatever database your app is using to make sure sleep and wake times are accurate. Wearable and non wearable technology may be more reliable in conjunction with an app.
Although use of sleep trackers may be a helpful first step in addressing your sleep habits, they should not be used as a replacement for medical evaluation. There is ongoing debate about the effectiveness of sleep trackers in comparison to lab based sleep tests, or polysomnography (PSG). Research in the subject is growing, but there are still many issues to be addressed. Sleep tracking devices can do something that PSG cannot however: data from thousands of people can be recorded. Therefore, sleep trackers serve an important purpose by analyzing sleep data on a population level.
Rise:
UCSB has recently paired with the sleep debt tracker app Rise, giving UCSB students four years of free use. Rise uses data from apple heath and is based on phone-motion sleep detection which uses steps and movement to make predictions about sleep. Rise can also work in conjunction with many third party sleep trackers such as fitbit and apple watch.
Rise is primarily a sleep debt tracker and works by predicting how much sleep debt you have each day (sleep debt refers to sleeping fewer hours than your body needs) based on sleep tracking data. However, the app provides a lot of other information such as your ideal time to go to bed and wake up, what time to avoid electronics, and dips in the day when your energy might increase or decrease. The specifics above are all personalized given your specific data. Rise also has a smart alarm function that will help you to wake up and feel refreshed.
https://www.risescience.com/edu
Comparing Sleep Trackers
In a study done by Grandner et. al, experimenters wanted to analyze the effectiveness of a group of sleep trackers. 34 young adults spent 3 consecutive nights in a sleep lab where they wore a selection of different wearable and non wearable sleep trackers. Results suggested that Fitbit was best for detecting light sleep and REM and Garmin devices were more efficient for analysis of deep sleep. Overall, fatigue science, fitbit, earlysense, resmed, and sleep score performed best out of the group. Researchers concluded that the commercial grade devices performed about as well as scientific grade actigraphy (medical-grade wearable technology), the only difference being they are for commercial use rather than for research.⁴
Concerns:
Few studies compare the performance of consumer wearable devices to gold standard polysomnography, which records brain waves, oxygen levels in blood, heart rate, and eye and leg movements. While some wearable devices use microphones to detect sleep apnea, other noise might intervene with the recording. Additionally, sleep trackers can underestimate the degree of wakefulness during sleep and overestimate duration of sleep. Sleep trackers may not be best suited for people with sleep disorders as their performance can decline with increased sleep disruption. Across populations, there is some discrepancy about the effectiveness of blood oxygen saturation and heart rate measurement using PPG (Finger photoplethysmography).
Sophia is a Sleep Health Intern at the Department of Health & Wellness
References
¹Goldstein, C. (2020). Current and future roles of consumer sleep technologies in sleep medicine. Sleep Medicine Clinics, 15(3), 391-408.
²Best sleep trackers of 2023. Sleep Foundation. (2023, February 17). Retrieved February 22, 2023, from https://www.sleepfoundation.org/best-sleep-trackers
³Best sleep trackers of 2023. Sleep Foundation. (2023, February 17). Retrieved February 22, 2023, from https://www.sleepfoundation.org/best-sleep-trackers
⁴Grandner, M. A., Lujan, M. R., & Ghani, S. B. (2021). Sleep-tracking technology in scientific research: looking to the future. Sleep, 44(5), zsab071.