For how we live.
Sensors and reminder inhalers get patients to take more doses — one trial lifted adherence from 30% to 84%. That this translates into meaningfully better control is real but a smaller effect.
A prescribed home apnea test can diagnose clear-cut cases, and one under-mattress sensor flagged severe apnea with 86% sensitivity — but both miss milder disease and events a lab would catch.
Toilet seats and mirrors that read your heart and blood pressure are real engineering. The published validation is mostly small, single-lab or company-run — and outcome evidence is absent.
A meta-analysis of consumer neurofeedback found no benefit for cognition, mindfulness or physical health and only a small effect on distress — even though the headbands do record real brain activity.
Consumer kits reliably estimate sperm concentration, and a smartphone assay matched lab classification ~98% of the time. But a normal count can't rule out the motility, shape and DNA problems a full analysis checks.
Pooled across 216 participants, the devices beat control by 45.3% on inflammatory lesions. The trials are small, none of the devices tested is necessarily one now sold, and the market is barely regulated.
Head-to-head against an ECG chest strap, popular optical wrist devices differed substantially, and one graded test found a smartwatch running a couple of beats low with a 28-bpm spread in its limits of agreement.
In a free-living comparison, three devices counted steps within about 18% of a research monitor but one overestimated active-calorie burn by 139%. A lab study found step counts collapse when walking is slow.
Smart-ring studies report flagging COVID nearly three days before symptoms and IBD flares weeks ahead. But two-thirds of that research carries a high risk of bias, and clinical usefulness is largely unproven.
A network meta-analysis put pooled accuracy for the fertile window at 0.88, best in the three days around ovulation. A wrist-temperature study hit ovulation within three days about 78% of the time.
Against a laboratory gas-exchange test, the Series 10 underestimated VO2 max by about 6 mL/kg/min on average, with wide limits of agreement. It reads trends better than absolute numbers.
Pooled across dozens of trials, activity trackers add roughly 1,800 steps a day and about 1 kg of weight loss. Effects on blood pressure, cholesterol and blood sugar are small and often not significant.
A review found wearables gave valid maximal-oxygen-uptake estimates in most studies of untrained and recreational exercisers. A separate meta-analysis pooled a 0.83 correlation, with high variability.
Against an ECG over 536 nights, Oura's heart-rate-variability error was under 8% and Whoop's acceptable, while Garmin and Polar lagged. The recovery scores layered on top stay proprietary and largely unvalidated.
A smartwatch bioimpedance sensor tracked body-fat percentage against DXA with about 14% average error — but muscle-mass agreement was weak, and even sitting versus standing shifted the reading.
Across 111 runners completing up to four trials each, two consumer devices tracked the direction of fluid loss reasonably well but missed the amount by 25% to 33% on average.
Twenty untrained women cycled at four fixed workloads wearing four popular low-cost bands, checked against indirect calorimetry. Every device drifted further from the truth as effort rose.
One lab test measured 4.7% sensitivity for falls from a wheelchair. Crash Detection has flooded some 911 centres with automated calls from ski slopes and roller coasters.