Skip to main content
KnowYourPrime

KnowYourPrime Evidence Registry

Permanent, citable records of how strong the published evidence is for specific claims about wearable health metrics. Each finding has a fixed ID, a rating set by a fixed rule, the studies behind it and a dated version history.

Findings

Showing all 25 findings

IDFindingMeasurementRatingVersionReviewed
KYP-ER-0001Smartwatch Blood Oxygen (SpO2) Accuracy Against Arterial Blood (SaO2)Blood oxygen (SpO2)Uncertain1.1October 25, 2026
KYP-ER-0002Pulse Oximeter Accuracy and Skin ToneBlood oxygen (SpO2)Uncertain1.0October 24, 2026
KYP-ER-0003Wearable HRV Accuracy Against ECGHeart rate variability (HRV)Uncertain1.0October 24, 2026
KYP-ER-0004Chest Strap HRV Accuracy Against ECGHeart rate variability (HRV)Established1.0October 24, 2026
KYP-ER-0005Readiness and Recovery Score ValidityReadiness and recovery scoresUncertain1.0October 24, 2026
KYP-ER-0006Work Stress and HRVHeart rate variability (HRV)Emerging1.0October 24, 2026
KYP-ER-0007Wearable Sleep Tracking Accuracy Against a Sleep LabSleepUncertain1.0October 24, 2026
KYP-ER-0008Under-Mattress Sleep Sensor AccuracySleepUncertain1.0October 24, 2026
KYP-ER-0009Wearable Heart Rate AccuracyHeart rateEstablished1.0October 24, 2026
KYP-ER-0010Wearable Calorie and Energy Expenditure AccuracyCalories (energy expenditure)Uncertain1.1October 24, 2026
KYP-ER-0011Wearable VO2 Max Estimate AccuracyVO2 max (cardio fitness)Emerging1.0October 24, 2026
KYP-ER-0012Do Activity Trackers Make People More Active?Physical activityUncertain1.0October 24, 2026
KYP-ER-0013Overnight HRV Drop Before an InfectionHeart rate variability (HRV)Emerging1.0October 24, 2026
KYP-ER-0014Normal HRV Range by AgeHeart rate variability (HRV)Established1.0October 24, 2026
KYP-ER-0015VO2 Max by Age and Sex: US Reference StandardsVO2 max (cardio fitness)Established1.1October 24, 2026
KYP-ER-0016Wearable Sleep Stage AccuracySleepUncertain1.0October 24, 2026
KYP-ER-0017Can Blood Oxygen Monitoring Rule Out Sleep Apnea?Blood oxygen (SpO2)Uncertain1.0October 24, 2026
KYP-ER-0018Smartwatch Blood Oxygen Accuracy at AltitudeBlood oxygen (SpO2)Uncertain1.0October 24, 2026
KYP-ER-0019Blood Oxygen Readings With Poor CirculationBlood oxygen (SpO2)Uncertain1.2October 24, 2026
KYP-ER-0020Accuracy of Smartwatches With a Built-In Blood Pressure CuffBlood pressureUncertain1.0October 24, 2026
KYP-ER-0021Cuffless Blood Pressure Accuracy at NightBlood pressureUncertain1.0October 24, 2026
KYP-ER-0022Do Calibrated Cuffless Blood Pressure Readings Track Real Changes?Blood pressureUncertain1.0October 24, 2026
KYP-ER-0023Apple Watch Blood Oxygen Accuracy Against Medical DevicesBlood oxygen (SpO2)Uncertain1.2October 27, 2026
KYP-ER-0024Oura Ring HRV Accuracy Against ECGHeart rate variability (HRV)Established1.0October 24, 2026
KYP-ER-0025Apple Watch HRV Accuracy Against ECG and Chest StrapsHeart rate variability (HRV)Uncertain1.0October 24, 2026

What a finding is

A finding is one question about a wearable measurement, such as whether a smartwatch blood oxygen reading matches arterial blood, rated against every study KnowYourPrime has scored for it. The record states the question, the rating, a plain answer, the key numbers, what the finding does and does not cover, its limitations and the full list of studies with their roles. The long-form analysis behind each finding sits on its research desk, linked from the finding; the Registry is the citable record of where that analysis stands.

How ratings are set

Each study is assigned a role for the claim: an anchor the rating can rest on, a supporting study, a conflicting study or a null result. A fixed rule turns those roles into one of five ratings, so the same evidence always produces the same rating. The rule and its version are shown on every finding.

The full rule is set out in the methodology and how KnowYourPrime interprets evidence.

Versions, review dates and corrections

A finding always carries the current rating on its research desk. When the evidence moves the rating, the finding gets a new major version (2.0, 3.0); when its text is revised, a new minor version (1.1, 1.2). Each version is dated and says what changed, and earlier versions stay listed. Errors are corrected the same way, as a new dated version, and can be reported to corrections@knowyourprime.com.

How to cite a finding

KnowYourPrime Evidence Registry, Finding [ID], version [version], reviewed [date]. [URL]

Every finding prints its own completed citation line, and the same line appears in its JSON and Markdown versions. Cite the page URL, not the JSON or Markdown file.