--- title: "Under-Mattress Sleep Sensor Accuracy | KnowYourPrime Evidence Registry" description: "Finding KYP-ER-0008, rated Uncertain. It finds sleep almost every time and misses most waking time, so it overstates how long you slept. In a sleep lab the Withings Sleep Analyzer overstated sleep by 48 minutes; at home the gap was smaller, and its sleep stage estimates were further off than its..." url: https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy --- KnowYourPrime Evidence Registry · Finding KYP-ER-0008 # Under-Mattress Sleep Sensor Accuracy Question assessedDoes an under-mattress sleep sensor agree with polysomnography? KnowYourPrime evidence rating Uncertain Evidence is conflicting, inconsistent, or difficult to interpret. It finds sleep almost every time and misses most waking time, so it overstates how long you slept. In a sleep lab the Withings Sleep Analyzer overstated sleep by 48 minutes; at home the gap was smaller, and its sleep stage estimates were further off than its sleep and wake calls. Finding KYP-ER-0008 Version 1.0 Reviewed October 24, 2026 Rating rule 1.6 [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) ## Why this is rated Uncertain An under-mattress sensor reads breathing and body movement through the mattress. Lying still awake looks much like sleep to it, which is why its errors run in one direction. Two studies of the same device, one in a lab and one at home, both reach the same mixed result: strong at detecting sleep, weak at detecting wake. Neither cleanly affirms agreement with polysomnography, so the rule rates the claim Uncertain. How the rating rule reads this evidence - An anchor study was assessed but its own reported finding supports this claim only weakly, so the evidence is treated as unsettled rather than affirming. - An anchor study was assessed but its own reported finding supports this claim only weakly, so the evidence is treated as unsettled rather than affirming. ## Key results - In 183 participants over more than 400 lab nights, the Withings Sleep Analyzer classified sleep and wake with 83 percent accuracy, caught 95 percent of sleep and 37 percent of wake, and overestimated total sleep time by 48 minutes while underestimating wake after sleep onset by 54 minutes. (Manners et al., Journal of Sleep Research, 2025) - At home in 117 healthy adults, accuracy was 87 percent with 93 percent sensitivity to sleep and 73 percent to wake, while sleep stage accuracy fell to 63 percent (kappa 0.49), overestimating light sleep by 1 hour 21 minutes and underestimating deep sleep by 46 minutes. (Stefanos et al., JMIR Human Factors, 2026) ## What this finding covers **Applies to:** The Withings Sleep Analyzer under-mattress sensor compared with simultaneous polysomnography, in a lab with and without sleep disorders and at home in healthy adults. **Does not cover:** Other under-mattress or smart mattress products; sleep apnea detection; wrist and ring trackers, covered in a separate finding. ## Limitations - Both studies tested one device; the home study and a grant behind the lab study have Withings funding or support. - Two studies are a small base for a device category. ## Evidence base 3 studies scored · 2 anchor · 1 supporting · Evidence last evaluated Oct 17, 2026 ### Anchor studies The studies the rating rests on. 1. Evaluation of a Contactless Sleep Monitoring Device for Sleep Stage Detection at Home in a Healthy Population: Prospective Study in Free-Living Conditions.Stefanos et al., JMIR Human Factors, 2026. [doi.org/10.2196/77033](https://doi.org/10.2196/77033) \[author affiliations include Withings\] 2. Performance evaluation of an under-mattress sleep sensor versus polysomnography in > 400 nights with healthy and unhealthy sleep.Manners et al., Journal of Sleep Research, 2025. [doi.org/10.1111/jsr.14480](https://doi.org/10.1111/jsr.14480) \[conflict statement: two authors had a Withings-supported research grant\] ### Supporting studies Studies consistent with the claim that do not carry the rating on their own. 1. Diagnostic value of wearable and contactless technologies for detecting obstructive sleep apnea: a systematic review and meta-analysis.Hasanain et al., Sleep & Breathing, 2025. [doi.org/10.1007/s11325-025-03544-4](https://doi.org/10.1007/s11325-025-03544-4) ## Version history | Version | Date | Rating | Change | | --- | --- | --- | --- | | 1.0 | October 24, 2026 | Uncertain | First published. | Rating history on the research desk: Uncertain (September 29, 2026). ## Cite this finding KnowYourPrime Evidence Registry, Finding KYP-ER-0008, version 1.0, reviewed 2026-10-24. https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy Machine-readable: [JSON](https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy.json) · [Markdown](https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy.md) · [All findings](https://knowyourprime.com/evidence) ## Related - Research desk: [the sleep research desk entry for this question](https://knowyourprime.com/research-desk-sleep#nearable_accuracy), with every scored study and its role - Related finding: [Wearable Sleep Tracking Accuracy Against a Sleep Lab](https://knowyourprime.com/evidence-wearable-sleep-tracking-accuracy) (KYP-ER-0007) - On this site: [Under-Mattress Sleep Tracker Accuracy vs Wearables: Sleep-Lab Results](https://knowyourprime.com/under-mattress-sleep-tracker-vs-wearable-accuracy) This is KnowYourPrime's own assessment of the published evidence, rated under the [KnowYourPrime evidence methodology](https://knowyourprime.com/methodology). The rating is set by a fixed rule from the roles of the studies above and moves only when the evidence or the rule changes. Every change to the rating or the text is published as a new dated version. To report an error, write to [corrections@knowyourprime.com](mailto:corrections@knowyourprime.com). ```json { "@context": "https://schema.org", "@type": "Article", "@id": "https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy#finding", "headline": "Under-Mattress Sleep Sensor Accuracy", "name": "KnowYourPrime Evidence Registry, Finding KYP-ER-0008: Under-Mattress Sleep Sensor Accuracy", "license": "https://creativecommons.org/licenses/by/4.0/", "description": "It finds sleep almost every time and misses most waking time, so it overstates how long you slept. In a sleep lab the Withings Sleep Analyzer overstated sleep by 48 minutes; at home the gap was smaller, and its sleep stage estimates were further off than its sleep and wake calls.", "url": "https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy", "identifier": { "@type": "PropertyValue", "propertyID": "KnowYourPrime Evidence Registry finding ID", "value": "KYP-ER-0008" }, "version": "1.0", "datePublished": "2026-10-24", "dateModified": "2026-10-28", "inLanguage": "en", "isPartOf": { "@type": "CreativeWorkSeries", "name": "KnowYourPrime Evidence Registry", "url": "https://knowyourprime.com/evidence" }, "author": { "@type": "Organization", "name": "KnowYourPrime", "url": "https://knowyourprime.com" }, "publisher": { "@type": "Organization", "@id": "https://knowyourprime.com/#organization", "name": "KnowYourPrime", "url": "https://knowyourprime.com" }, "about": "Does an under-mattress sleep sensor agree with polysomnography?", "citation": [ { "@type": "ScholarlyArticle", "name": "Evaluation of a Contactless Sleep Monitoring Device for Sleep Stage Detection at Home in a Healthy Population: Prospective Study in Free-Living Conditions.", "url": "https://doi.org/10.2196/77033", "datePublished": "2026", "isPartOf": { "@type": "Periodical", "name": "JMIR Human Factors" } }, { "@type": "ScholarlyArticle", "name": "Performance evaluation of an under-mattress sleep sensor versus polysomnography in > 400 nights with healthy and unhealthy sleep.", "url": "https://doi.org/10.1111/jsr.14480", "datePublished": "2025", "isPartOf": { "@type": "Periodical", "name": "Journal of Sleep Research" } }, { "@type": "ScholarlyArticle", "name": "Diagnostic value of wearable and contactless technologies for detecting obstructive sleep apnea: a systematic review and meta-analysis.", "url": "https://doi.org/10.1007/s11325-025-03544-4", "datePublished": "2025", "isPartOf": { "@type": "Periodical", "name": "Sleep & Breathing" } } ], "encoding": [ { "@type": "MediaObject", "encodingFormat": "application/json", "contentUrl": "https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy.json" }, { "@type": "MediaObject", "encodingFormat": "text/markdown", "contentUrl": "https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy.md" } ] } ``` ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://knowyourprime.com/"},{"@type":"ListItem","position":2,"name":"Evidence Registry","item":"https://knowyourprime.com/evidence"},{"@type":"ListItem","position":3,"name":"Under-Mattress Sleep Sensor Accuracy"}]} ```