Sleep Trackers Offer Insights, But Experts Caution Against Obsession

Wearable devices can provide useful data, but users should understand their limitations and avoid fixating on the numbers.

Jan. 27, 2026 at 10:47am

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Millions of people use wearable devices like smartwatches and fitness trackers to monitor their sleep, but experts say these sleep trackers don't directly measure sleep. Instead, they infer sleep stages from signals like heart rate and movement. While the technology has become more accurate, experts caution that users should not take the data too literally or become overly obsessed with the numbers. They recommend using the devices to identify trends over time and develop better sleep habits, rather than fixating on a single night's data.

Why it matters

As the sleep-tracking device market continues to grow, it's important for users to understand the limitations of the technology and how to best utilize the data. Overreliance on the devices can lead to anxiety and a condition called "orthosomnia," where people become obsessed with achieving perfect sleep scores. Experts say the devices are most useful for identifying general sleep patterns and trends, not for precisely measuring sleep stages.

The details

Sleep trackers largely work by recording the wearer's movements and heart rate while at rest. Algorithms then infer sleep stages like REM and non-REM sleep. While these algorithms have become more accurate, an in-lab sleep study would still provide more precise data. Experts say users should focus on overall sleep quality and duration rather than granular details like REM sleep percentages. The devices can help users identify factors that impact their sleep, like alcohol consumption or late-night eating, and develop better sleep hygiene.

  • The U.S. sleep-tracking devices market generated about $5 billion in revenue in 2023.
  • The sleep-tracking devices market is expected to double in revenue by 2030, according to market research firm Grand View Research.

The players

Daniel Forger

A University of Michigan math professor who researches the science behind sleep wearables.

Dr. Chantale Branson

A neurologist and professor at the Morehouse School of Medicine who frequently sees patients concerned about their sleep tracker data.

Kate Stoye

An Atlanta-area middle school teacher who uses an Oura Ring to track her sleep and make lifestyle changes.

Mai Barreneche

An advertising professional in New York City who became "obsessed" with her sleep tracker data and decided to stop wearing the device.

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What they’re saying

“If you really want to know definitively how much non-REM sleep you're having versus REM sleep, that's where the in-lab studies really excel.”

— Daniel Forger, University of Michigan math professor (whec.com)

“We would have believed them with or without the device and worked on trying to figure out why they can't sleep — and that is what the wearables do not do.”

— Dr. Chantale Branson, Neurologist and professor at Morehouse School of Medicine (whec.com)

“Seeing if your biological clock is in sync is a huge benefit because even if you're giving yourself the right amount of time, if you're sleeping at the wrong times, the sleep won't be as efficient.”

— Daniel Forger, University of Michigan math professor (whec.com)

“I don't see much reason to drink if I know that it's going to affect how I feel.”

— Kate Stoye, Atlanta-area middle school teacher (whec.com)

“I remember I would go to bed thinking about the score I was going to get in the morning.”

— Mai Barreneche, Advertising professional in New York City (whec.com)

What’s next

Emerging research suggests sleep trackers could one day be designed to help detect infections before symptoms appear and flag sleep pattern changes that may signal the onset of depression or an increased risk of relapse.

The takeaway

While sleep trackers can provide useful insights and encourage better sleep habits, experts caution users against becoming overly obsessed with the data. The devices should be used to identify trends over time, not as a definitive measure of one's sleep health. Consulting a healthcare professional is recommended for those with significant sleep concerns.