Blog

Insights on health technology, privacy-first design, and the science behind smarter wearables.

LATEST ARTICLES

An ECG waveform diagram showing the difference between normal sinus rhythm and the chaotic irregular pattern of atrial fibrillation, illustrating what smart rings try to detect with PPG sensors

Your Smart Ring's AFib Detection Is Not Medical Grade. Here Is What It Actually Measures.

Smart rings use PPG sensors to detect patterns that may suggest atrial fibrillation. But PPG-based AFib detection is not medical-grade diagnosis. Here is how it works, what the accuracy actually looks like, and why the Circular Ring 2 with real ECG is the exception.

James Hoffmann

Jun 26, 2026 1 min read

A doctor reviewing patient data on a tablet, illustrating the gap between consumer wearable metrics and clinical usefulness

Wearable AccuracyDoctorClinical Data

Your Doctor Doesn't Want Your Wearable Data. Here Is What They Actually Want.

The NYT just published a piece on what health data doctors actually find useful. The answer is three metrics. Your smart ring gives you forty. Here is why that gap exists and what it means for products like Pulsyn.

James Hoffmann

Jun 25, 2026 1 min read

A transparent glass cube on a table, representing algorithmic clarity and openness in health technology

Algorithm TransparencyReproducibilityWearable Research

89% of Smart Ring Studies Use Algorithms Nobody Can See: The Transparency Crisis in Wearable Health

A new systematic review finds 89% of smart ring studies rely on proprietary algorithms that nobody outside the company can inspect. Here is what that means for the data on your wrist (or finger).

James Hoffmann

Jun 25, 2026 1 min read

An airplane window view at cruising altitude showing clouds and wing, with a smart ring on a finger in the foreground

TravelCabin PressureSpO2

Your Smart Ring Lies to You at 35,000 Feet: How Cabin Pressure Breaks SpO2, HRV, and Your Recovery Score

Your smart ring was validated at sea level on healthy volunteers. At 35,000 feet in a pressurized cabin, the SpO2 calibration curve is wrong, your HRV is falsely depressed, and your recovery score takes a hit that has nothing to do with how recovered you actually are. Here is the physiology of flying and why your ring does not understand it.

James Hoffmann

Jun 24, 2026 1 min read

A thermometer showing extreme summer temperatures against a hazy sky, representing how heat waves affect smart ring biometric readings

HeatVasodilationPpg Accuracy

Why Heat Waves Break Your Smart Ring's Biometrics: The Vasodilation Problem Nobody Mentions

Smart rings measure your finger. In a heat wave, your finger is a completely different physiological environment. Here is what actually happens to your biometrics when the temperature passes 35°C.

James Hoffmann

Jun 24, 2026 1 min read

Prescription medication pills on a dark surface, representing GLP-1 drugs like Ozempic and Wegovy

Heart RateOn Device AiHrv

What GLP-1 Drugs Do to Your Smart Ring's Readings

GLP-1 drugs like Ozempic and Wegovy increase your resting heart rate by 2-5 bpm, lower HRV, and change skin temperature. Here is how that breaks every wearable algorithm and why your recovery score is lying to you.

James Hoffmann

Jun 23, 2026 1 min read

A glucose test strip and blood sample, representing the new frontier of continuous glucose monitoring data that Oura is now integrating into its platform

HipaaPrivacyOura

Oura Is Tracking Your Blood Sugar Now. Your Insurance Company Will Want That Data.

Oura just integrated with Dexcom Stelo for continuous glucose monitoring. Here is what happens when your sleep tracker knows your blood sugar, and why your insurance company will want that data on a server.

James Hoffmann

Jun 23, 2026 1 min read

A person sleeping on their side with a smart ring on their finger, illustrating how body position compresses the finger against a pillow or mattress

PpgAccuracySleep

Why Your Smart Ring's Nighttime Data Is a Lie: The Sleep Position Problem Nobody Mentions

Your smart ring's PPG sensor assumes your finger is at heart level with unrestricted blood flow. When you sleep on your side, neither of those things is true. Here is what the data actually looks like.

James Hoffmann

Jun 21, 2026 1 min read

A pregnant woman wearing a smart ring, with abstract biometric data lines flowing around her finger

Heart RateBiometricsAlgorithms

Your Smart Ring Has No Idea You're Pregnant: How Pregnancy Breaks Every Biometric Algorithm

Pregnancy raises your resting heart rate by 10 to 20 bpm, drops your HRV, raises your temperature, and changes your sleep architecture. Every wearable algorithm trained on non-pregnant baselines gets this wrong. Here is what the data actually looks like.

James Hoffmann

Jun 21, 2026 1 min read