Wearables
Oura vs Whoop vs Eight Sleep, and the accuracy of consumer wearables versus lab references.
If you only read one
Apple Watch health features: what's regulated and what's wellness
Apple Watch's ECG, AFib detection, sleep apnoea notifications, fall detection, and SpO2 — what's actually FDA-authorised or FDA-cleared as a medical feature, what's wellness, and what each does in practice.
Grade B · 4 min read · Last reviewed 2026-05-19
Apple Watch health features: what's regulated and what's wellness
Evidence BApple Watch's ECG, AFib detection, sleep apnoea notifications, fall detection, and SpO2 — what's actually FDA-authorised or FDA-cleared as a medical feature, what's wellness, and what each does in practice.
4 min read · Last reviewed 2026-05-19
CGM wellness products (Lingo, Stelo, Levels, ZOE): what they actually offer
Evidence BContinuous glucose monitors are now sold direct-to-consumer for wellness use. What each product actually provides, where the value is, and the regulatory and clinical considerations.
4 min read · Last reviewed 2026-05-19
How accurate are consumer wearables? A look at validation studies
Evidence BHeart rate, HRV, sleep stages, SpO2 — what the published validation literature actually shows about consumer wearables versus laboratory reference measurements.
3 min read · Last reviewed 2026-05-17
What is Garmin Body Battery? How the score works and how to read it
Evidence CWhat is Garmin Body Battery? Garmin's 5–100 energy-reserve score built from HRV, sleep, stress, and activity. The inputs are independently validated; the composite isn't. How to read it, device and subscription status, and how it compares to Whoop, Oura, and Apple's new Readiness score.
11 min read · Last reviewed 2026-09-23
Oura vs Whoop vs Eight Sleep: what each one is actually good at
Evidence BThree of the most popular sleep and recovery wearables, what they measure differently, and the validation literature for each.
3 min read · Last reviewed 2026-05-17
Smart ring comparison 2026: Oura, Galaxy Ring, RingConn, Ultrahuman
Evidence BSmart ring comparison 2026: UK prices, battery life, subscription costs, sizing and validation evidence for Oura Ring 4, Galaxy Ring, RingConn Gen 2 and Ultrahuman Ring AIR — who wins for sleep, budget and no-subscription use.
14 min read · Last reviewed 2026-09-23
Smart scales and body composition (BIA): what the numbers actually mean
Evidence CSmart scales using bioelectrical impedance (BIA) estimate body composition. Withings, Garmin, Eufy, and Omron are common UK options. What's accurate, what's noisy, and what to track.
4 min read · Last reviewed 2026-05-19
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