Your watch says you had three hours of deep sleep. Should you believe it?
\nMillions of people rely on phone apps and wearable devices like rings, smartwatches and sensors to monitor how well they’re sleeping, but these trackers don\u2019t necessarily measure sleep directly. Instead, they infer states of slumber from signals like heart rate and movement, raising questions about how reliable the information is and how seriously it should be taken.
\nThe U.S. sleep-tracking devices market generated about $5 billion in 2023 and is expected to double in revenue by 2030, according to market research firm Grand View Research. As the devices continue to gain popularity, experts say it is important to understand what they can and cannot tell you, and how their data should be used.<\/p>\n
Whether it’s an Apple Watch, a Fitbit, an Oura Ring or one of innumerable other competitors, health and fitness trackers largely take the same basic approach by recording the wearer’s movements and heart rate while at rest, according to Daniel Forger, a University of Michigan math professor who researches the science behind sleep wearables.
\nThe algorithms used by major brands have become highly accurate for determining when someone is asleep, Forger said. The devices are also somewhat helpful for estimating sleep stages, though an in-lab study would be more precise, he said.
\n\u201cIf you really want to know definitively how much non-REM sleep you\u2019re having versus REM sleep, that\u2019s where the in-lab studies really excel,\u201d Forger said.<\/p>\n
Dr. Chantale Branson, a neurologist and professor at the Morehouse School of Medicine, said she frequently has patients showing up with sleep scores from fitness trackers in hand, sometimes fixated on granular details such as how much REM sleep they got on a certain night.
\nBranson says those patients are taking the wrong approach: the devices help highlight trends over time but should not be viewed as a definitive measure of one’s sleep health. Nor should any single night’s data be seen as significant.
\n\u201cWe would have believed them with or without the device and worked on trying to figure out why they can’t sleep \u2014 and that is what the wearables do not do,\u201d she said.
\nBranson said she thinks people who check their sleep statistics every morning would be better served by spending their efforts on \u201csleep hygiene\u201d such as creating a relaxing bedtime routine, avoiding screens before bed and making sure their sleep environment is comfortable. She advises those concerned about their sleep to consult a clinician before spending money on a wearable.
\nForger takes a more favorable view toward the devices, which he says help keep the overlooked importance of sleep front of mind. He recommends them even for people without significant sleep issues, saying they can offer insights that help users fine-tune their routines and feel more alert during the day.
\n\u201cSeeing if your biological clock is in sync is a huge benefit because even if you\u2019re giving yourself the right amount of time, if you\u2019re sleeping at the wrong times, the sleep won\u2019t be as efficient,\u201d Forger said.<\/p>\n
Kate Stoye, an Atlanta-area middle school teacher, bought an Oura Ring last summer, having heard positive things from friends who used it as a fertility tracker: \u201cIt\u2019s so accurate,\u201d she said. Stoye found the ring to be just as helpful with tracking her sleep. After noticing that the few nights she drank alcohol coincided with poorer sleep quality, she decided to give up alcohol.
\n\u201cI don\u2019t see much reason to drink if I know that it\u2019s going to affect how I feel,\u201d said Stoye, who always wears her device except when she is playing tennis or needs to charge it.
\nAnother trend she says she detected in the ring’s data: the importance of not eating too late if she wants to get good rest.
\n\u201cI always struggle with going to bed, and it\u2019s often because I eat late at night,\u201d Stoye said. \u201cI know that about myself, and it knows it too.\u201d<\/p>\n
Mai Barreneche, who works in advertising in New York City, used to wear her Oura Ring constantly. She said it helped her develop good sleep habits and encouraged her to maintain a daily morning exercise regimen. But as a metric-driven person, she became "obsessed" enough with her nightly sleep scores that it began to cause her anxiety \u2014 a modern condition that researchers have dubbed \u201corthosomnia.\u201d
\n\u201cI remember I would go to bed thinking about the score I was going to get in the morning,\u201d Barreneche said.
\nBarreneche decided not to wear her ring on a beach vacation a few years ago, and when she returned home, she never put it back on. She said she has maintained the good habits the device pointed her toward, but no longer wants the stress of monitoring her nightly scores.
\nBranson, of the Morehouse School of Medicine, said she’s observed similar score-induced anxiety as a recurring issue for some patients, particularly those who set goals to achieve a certain amount of REM sleep or who shared their nightly scores with friends using the same device. Comparing sleep types and stages is ill-advised since individual needs vary by age, genetics and other factors, she said.
\n\u201cThese devices are supposed to help you," Branson said. "And if you feel anxious or worried or frustrated about it, then it\u2019s not helpful, and you should really talk to a professional.\u201d<\/p>\n
Forger thinks the promise of wearables has been underestimated, with emerging research suggesting the devices could one day be designed to help detect infections before symptoms appear and to flag sleep pattern changes that may signal the onset of depression or an increased risk of relapse.
\n\u201cThe body is making these really interesting and really important decisions that we\u2019re not aware of to keep us healthy and active and alert at the right times of day,\u201d he said. \u201cIf you have an infection, that rhythm very quickly starts to disappear because the body goes into overdrive to start fighting the infection. Those are the kind of things we can pick up.\u201d
\nThe technology could be particularly useful in low-resource communities, where wearables could help health issues to be identified more quickly and monitored remotely without requiring access to doctors or specialized clinics, according to Forger.
\n\u201cThere\u2019s this really important story that\u2019s about to come out: About just how understanding sleep rhythms and sleep architecture is going to generally improve our lives,\u201d he said.<\/p>\n
Sleep-tracking devices have become increasingly popular in recent years, with millions of people relying on them to monitor their sleep quality. While these devices can provide valuable insights into sleep patterns and help users develop better sleep habits, they also have limitations and potential drawbacks. It is essential to understand what these devices can and cannot do and to use their data in a way that is helpful, rather than harmful.<\/p>\n
Q: What do sleep-tracking devices actually measure?
\nA: Sleep-tracking devices measure movement and heart rate while at rest, using algorithms to infer states of sleep.
\nQ: Are sleep-tracking devices accurate?
\nA: The algorithms used by major brands have become highly accurate for determining when someone is asleep, but may not be as precise for estimating sleep stages.
\nQ: Can sleep-tracking devices help with sleep disorders?
\nA: While sleep-tracking devices can provide valuable insights into sleep patterns, they should not be relied upon as the sole diagnostic tool for sleep disorders. Consult a clinician for proper diagnosis and treatment.
\nQ: Can sleep-tracking devices cause anxiety?
\nA: Yes, some people may experience anxiety or stress related to their sleep scores, particularly if they become overly fixated on achieving certain sleep goals.
\nQ: What is the future of sleep-tracking devices?
\nA: Emerging research suggests that sleep-tracking devices could one day be designed to help detect infections, flag sleep pattern changes that may signal the onset of depression, and improve overall health and well-being.<\/p>\n","protected":false},"excerpt":{"rendered":"
Introduction to Sleep-Tracking Devices Your watch says you had three hours of deep sleep. Should you believe it? Millions of people rely on phone apps and wearable devices like rings, smartwatches and sensors to monitor how well they’re sleeping, but these trackers don\u2019t necessarily measure sleep directly. Instead, they infer states of slumber from signals […]<\/p>\n","protected":false},"author":2,"featured_media":36193,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rank_math_lock_modified_date":false,"footnotes":""},"categories":[26],"tags":[],"class_list":{"0":"post-36191","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health"},"jetpack_featured_media_url":"https:\/\/i1.wp.com\/media.nbcchicago.com\/2026\/01\/AP26023803703029.jpg?quality=85&strip=all&resize=1200%2C675&w=1200&resize=1200,675&ssl=1","_links":{"self":[{"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/posts\/36191"}],"collection":[{"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/comments?post=36191"}],"version-history":[{"count":1,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/posts\/36191\/revisions"}],"predecessor-version":[{"id":36194,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/posts\/36191\/revisions\/36194"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/media\/36193"}],"wp:attachment":[{"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/media?parent=36191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/categories?post=36191"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/citystuff.com\/chicago\/wp-json\/wp\/v2\/tags?post=36191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}