How Accurate Are Sleep Trackers? What Sleepmaxxing Measures

How accurate are sleep trackers? Consumer devices are good at telling whether you slept or lay awake, and they get imprecise once they split the night into sleep stages. A meta-analysis of 24 studies with 798 participants found that wrist-worn devices underestimate total sleep time by about 17 minutes on average. The question matters to more people every year, because more and more people measure their nights. In a June 2025 survey of 2,007 US adults by the American Academy of Sleep Medicine (AASM), 56 percent said they had tried at least one viral sleep trend. Nearly half, 48 percent, had already used a device to track their sleep, up from 35 percent in the same survey series in 2023. Tracking also has a side effect with its own name, orthosomnia. It means the pursuit of perfect sleep data, which can even make sleep worse.

What “sleepmaxxing” means

Sleepmaxxing is the umbrella term for deliberately investing in products and routines meant to optimize your own sleep quality. The word comes from social media. It names a pattern of consumption and self-optimization, not a medical category.

How widespread is it? In June 2025 the AASM had the firm Atomik Research survey 2,007 US adults. The margin of error was ±2 percentage points. The result: 56 percent had tried at least one current sleep trend. Sleepmaxxing in the narrow sense accounted for 12 percent, far less than the visibility of the word would suggest.

The age split stands out. Among 18- to 24-year-olds, 73 percent had tried such a trend, compared with 31 percent of adults over 65. Sleepmaxxing itself was named by 13 percent of 18- to 24-year-olds and by 3 percent of those over 65. The trend is real, then, but young, and smaller across the population than its echo online.

The figures come from a US sample. For Germany, where Qi Blanco is based, we found no comparable survey during research, so they stand here as figures for the US market.

How fast the measured night became normal

A sleep tracker is a device that records movement, pulse or breathing signals and uses an algorithm to infer sleep from them. The tracker does not measure sleep directly. The inference runs through proxy signals.

Adoption has shifted within a short time. In the AASM survey series, 35 percent of adults said in November 2023 that they had used an electronic sleep-tracking device. In the June 2025 wave the figure was 48 percent, with comparable methods and sample size. Within about two years the share rose by 13 percentage points.

The same survey breaks down which devices people use.

Device	Share of respondents
Smartphone with an app	23%
Smartwatch	20%
Fitness band	13%
Bedside device	8%
Smart bed or mattress	8%
Ring	7%
Sensor mat or pad	6%
None of these	52%

Two findings stand out. First, the majority, 52 percent, use no device at all; among adults over 65 the figure is 81 percent. Second, the most common tracking device is not a specialist gadget but the smartphone. The phone already lies next to the bed, and that placement is exactly where the measurement comes from.

How long people in Germany actually sleep

Short sleep duration, in official health statistics, means sleeping less than the seven hours recommended for adults. The measure describes the quantity of sleep, not its quality.

For Germany a current survey exists. In August 2026 the Robert Koch Institute, the German federal public health agency, published results from its study “German Health Update” (GEDA 2023). The study is a telephone survey of 8,026 adults conducted between May 2023 and February 2024. The core finding, in the authors’ words (our translation).

“Short sleep duration on weekdays is found in 39.6% of the adult population. Men report short sleep duration more often than women, particularly men aged 45 to 64 (53.0%).”

Kaufholdová, Richter, Saß, Schienkiewitz: Which population groups tend to sleep too little?, Journal of Health Monitoring, Robert Koch Institute, 2026

On weekends the share drops to 22.7 percent. During the week the night gets shorter, and part of that evens out on days off. The figure points less to a deficit that lasts all week.

The survey measures duration. What shortens the night, whether devices, screens or trends, was not its question.

What a wrist-worn sleep tracker really measures

Actigraphy is the practice of inferring sleep and wakefulness from movement data, usually supplemented by heart rate. No consumer wristband measures brain waves; the sleep verdict is a calculation.

A laboratory study in the journal SLEEP tested how well that calculation works. In the study, 34 healthy adults slept for three nights under full polysomnography, the instrument-based reference method that records brain waves, eye movements and muscle activity. During those nights they wore seven consumer devices at once.

The result splits in two:

• Detecting sleep: good. Sensitivity was at least 0.93 for all seven devices. When someone is asleep, the devices register it reliably.
• Detecting wakefulness: weak. Specificity ranged from 0.18 to 0.54. Short periods of waking at night are often booked as sleep.

The asymmetry explains a common experience. Someone who lies awake at night and sees a good sleep score in the morning usually does not have a faulty device. The score reflects the known weakness of the method: to a motion sensor, lying awake and still looks much like sleep.

Where sleep trackers diverge from the sleep lab

Polysomnography is the reference standard of sleep medicine, and deviations from it are reported as a mean difference in minutes. A 2025 meta-analysis in the Journal of Clinical Sleep Medicine pooled 24 studies with a total of 798 participants and compared wrist-worn devices against that reference.

Measure	Mean deviation from the lab
Total sleep time	−16.9 minutes (underestimated)
Sleep efficiency	−4.7 percentage points
Sleep onset latency	+2.6 minutes
Wake after sleep onset	+13.3 minutes

The size of the error is the real message. A gap of roughly a quarter of an hour in total sleep time hardly matters if you want to know whether you get roughly enough sleep. It does matter if you want to know whether last night was better than the night before. The difference between two nights often falls within the same range as the measurement error.

The authors consider the devices less reliable than polysomnography, but useful for following general sleep patterns over longer periods. A four-week trend therefore carries more weight than any single night. The accuracy of sleep stages was outside the scope of the analysis, as the paper itself notes.

Why sleep stages are the weakest number on the screen

Sleep stages divide the night into light sleep, deep sleep and REM sleep. Sleep medicine assigns them from brain-wave patterns, a signal that a wristband does not record.

The laboratory finding was clearest on exactly this point. The seven-device study reaches a short verdict.

“Device sleep stage assessments were inconsistent.”

Chinoy et al.: Performance of seven consumer sleep-tracking devices compared with polysomnography, SLEEP 44(5), 2021

In detail, every device tested overestimated light sleep, except one that underestimated it. Three devices deviated significantly on deep sleep, each one upward. Three others deviated on REM sleep, each one downward.

In practice, the deep-sleep minutes on the display are the least reliable number of the entire readout, and often the one people study most closely in the morning. In 2025 the World Sleep Society, the international professional body for sleep medicine, took up exactly this point in recommendations on wearables. Its task force called for uniform, disclosed baseline measures, kept clearly apart from proprietary metrics such as a “sleep score” whose calculation is not published. According to the task force, the value of such devices is still under discussion among specialists.

Orthosomnia: when tracking itself disturbs sleep

Orthosomnia is an excessive preoccupation with improving or perfecting one’s own sleep data. A research group led by Kelly Glazer Baron coined the term in 2017 in the Journal of Clinical Sleep Medicine, describing three patient cases.

“We termed this condition ‘orthosomnia,’ with ‘ortho’ meaning straight or correct, and ‘somnia’ meaning sleep, because patients are preoccupied or concerned with improving or perfecting their wearable sleep data.”

Baron, Abbott, Jao, Manalo, Mullen: Orthosomnia: Are Some Patients Taking the Quantified Self Too Far?, J Clin Sleep Med 13(2), 2017

What stands out in these cases is how the patients weighed the data. The tracker numbers felt more convincing to them than the measurement in the sleep lab, even where the devices are demonstrably inaccurate.

A 2024 cross-sectional study in Brain Sciences examined how common the pattern is. Of 523 respondents, 35.8 percent regularly used a sleep wearable. Depending on the definition, prevalence came out at 3.0 percent (narrow), 8.6 percent (moderate) and 14.0 percent (broad). Most respondents were young, with a median age of 21, and 81 percent were women.

The professional society itself sees both sides. Shalini Paruthi, a spokesperson for the AASM, said in January 2026.

“Sleep trackers can be valuable tools for raising awareness about sleep health and motivating positive changes in sleep habits. However, it’s important that tracking enhances sleep and doesn’t cause more stress about it.”

Shalini Paruthi, American Academy of Sleep Medicine, January 2026

The devices are not meant as diagnostic tools. A 2018 position statement from the same society states that consumer sleep technology cannot be used to diagnose or treat sleep disorders, because it lacks validation and regulatory clearance. If you feel your nights have been troubled for some time, the best person to talk to is a doctor.

What the phone next to the bed does at night besides tracking

A smartphone on standby is not a switched-off device. The phone stays registered on the cellular network through the night and briefly contacts the cell tower from time to time. It does so within arm’s reach of the head, because that is where it charges and where the alarm rings. In a 2024 survey of 1,007 people in Germany by Bitkom Research, 77 percent said they prefer to charge their smartphone overnight.

How often does it transmit? Germany’s Federal Office for Radiation Protection (BfS) says a phone on standby on the nightstand contacts the base station “only rarely and very briefly” and calls the resulting radiation “negligible”. Such contacts do happen over the course of a night, but by that account the phone is not transmitting continuously.

On the state of research, the same agency writes the following, as of January 30, 2026 (our translation).

“Neither experimental studies in test subjects nor observational studies in humans have been able to demonstrate a link between radio-frequency electromagnetic fields from mobile phones or mobile base stations and sleep disorders [...].”

Federal Office for Radiation Protection (BfS): Biological and health effects of radio-frequency fields under scientific discussion, as of 30.01.2026

So the phone transmits at intervals during the night, and the exposure limits protect against the heating of tissue. For 23 percent of respondents, the same device that lies next to their head at night is also the measuring instrument whose numbers set the tone in the morning. If you switch on airplane mode, the phone transmits less, and the alarm usually keeps working, as does the tracking in many apps.

What matters to Qi Blanco about sleep

What Qi Blanco builds is an experience in everyday life, and the jewelry is the vehicle for it. How we work, and which research we rely on for our own subjects, is open to everyone in our studies overview. More articles on sleep and everyday life are in our knowledge blog.

Frequently asked questions about sleep trackers

Are sleep trackers useless?

For a lot of things they work quite well. Consumer devices tell sleep from wakefulness with a sensitivity of at least 0.93, and they are good at showing patterns across weeks. They are weaker at catching brief waking periods (specificity 0.18 to 0.54) and at sleep stages.

Which number on the display is least reliable?

Sleep stages, deep sleep in particular. In the lab comparison of seven devices, the stage estimates were inconsistent. How proprietary composite values such as a “sleep score” are calculated is not disclosed either.

How far does a wrist-worn tracker deviate from the sleep lab?

By a good quarter of an hour on average. In the meta-analysis of 24 studies with 798 participants, wrist-worn devices underestimated total sleep time by 16.9 minutes and overestimated wake after sleep onset by 13.3 minutes.

What is orthosomnia?

The term describes an excessive preoccupation with perfecting your own sleep data. It was coined in 2017 from three patient cases. A 2024 survey found prevalence between 3.0 and 14.0 percent depending on the definition, and most of its respondents were young women.

Can a sleep tracker detect a sleep disorder?

That remains a job for a doctor. A 2018 AASM position statement says that consumer sleep technology cannot be used for diagnosis or treatment, because it lacks validation and regulatory clearance.

Key takeaways on sleep tracker accuracy

• The measured night is growing: in the US survey series, the share of adults who have used a sleep tracker rose from 35 percent (2023) to 48 percent (June 2025), and 52 percent use no such device.
• Sleepmaxxing is more visible than widespread: 12 percent of the 2,007 respondents reported it, against 56 percent for sleep trends overall.
• We found no comparable figures on these trends for Germany; the shares above describe the US market.
• What is measured for Germany is sleep duration: 39.6 percent of adults sleep short on weekdays and 22.7 percent on weekends (GEDA 2023, 8,026 respondents).
• Trackers detect sleep reliably (sensitivity at least 0.93) and waking far less well (specificity 0.18 to 0.54).
• The gap to the sleep lab is about 17 minutes of sleep time. That matters when you compare two single nights, and hardly at all for the rough question of whether you get enough sleep.
• Sleep stages are the weakest figure on the display; since 2025 the World Sleep Society has called for disclosed, uniform baseline measures.
• Orthosomnia describes the case in which tracking itself becomes a burden. That is one more reason the weekly trend deserves more attention than any single night.
• For 23 percent of respondents, the smartphone next to the bed is both tracker and radio. According to Germany’s Federal Office for Radiation Protection, on standby it contacts the cell tower “only rarely and very briefly”.

Sources and further reading

• American Academy of Sleep Medicine: AASM Sleep Prioritization Survey: Social Media Sleep Trends. Survey of 2,007 adults by Atomik Research, June 5–13, 2025. Data sheet (PDF)
• American Academy of Sleep Medicine: AASM Sleep Prioritization Survey: Using Sleep Tracking Devices. Fielded June 2025, published January 2026. Data sheet (PDF)
• American Academy of Sleep Medicine: One in three Americans have used electronic sleep trackers. News release, November 15, 2023. AASM news release
• American Academy of Sleep Medicine: Sleep tracking and sleepmaxxing change bedtime behaviors. News release, January 26, 2026, with a quote from Shalini Paruthi. AASM news release
• Evan D. Chinoy et al.: Performance of seven consumer sleep-tracking devices compared with polysomnography. SLEEP 44(5), zsaa291, 2021. DOI: 10.1093/sleep/zsaa291. Full text at PubMed Central
• Young Jeong Lee et al.: Performance of consumer wrist-worn sleep tracking devices compared to polysomnography: a meta-analysis. Journal of Clinical Sleep Medicine 21(3), pages 573–582, March 2025. DOI: 10.5664/jcsm.11460. Full text at PubMed Central
• Kelly Glazer Baron et al.: Orthosomnia: Are Some Patients Taking the Quantified Self Too Far? Journal of Clinical Sleep Medicine 13(2), pages 351–354, 2017. DOI: 10.5664/jcsm.6472. Full text at PubMed Central
• Haitham Jahrami et al.: Prevalence of Orthosomnia in a General Population Sample: A Cross-Sectional Study. Brain Sciences 14(11), 1123, 2024. DOI: 10.3390/brainsci14111123. Full text at PubMed Central
• Seema Khosla et al.: Consumer Sleep Technology: An American Academy of Sleep Medicine Position Statement. Journal of Clinical Sleep Medicine 14(5), pages 877–880, 2018. DOI: 10.5664/jcsm.7128. Full text at PubMed Central
• Michael W. L. Chee et al. (World Sleep Society Sleep Tracker Task Force): World Sleep Society recommendations for the use of wearable consumer health trackers that monitor sleep. Sleep Medicine 131, 106506, July 2025. DOI: 10.1016/j.sleep.2025.106506
• Zuzana Kaufholdová, Antje Richter, Anke-Christine Saß, Anja Schienkiewitz: Welche Bevölkerungsgruppen schlafen eher zu wenig? Ergebnisse der Studie „Gesundheit in Deutschland aktuell“ (GEDA 2023). Journal of Health Monitoring, Robert Koch Institute, August 2026, in German. Telephone survey of 8,026 adults. Full text in the RKI repository
• Federal Office for Radiation Protection (BfS): Wissenschaftlich diskutierte biologische und gesundheitliche Wirkungen hochfrequenter Felder. As of January 30, 2026, in German. BfS page
• Federal Office for Radiation Protection (BfS): Auswirkungen hochfrequenter elektromagnetischer Felder auf Gehirnaktivität und Schlaf. As of July 2, 2026, in German. BfS page
• Bitkom e. V.: Three quarters charge their smartphone overnight. Survey of 1,007 people by Bitkom Research, 2024, in German. Press release