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Health technology, privacy-first design, and the research behind what a ring can actually measure.

A smartphone screen showing a minimal dark interface without login forms or password fields

Latest Privacy · Rune 1 How Pulsyn Works Without a Login Screen Most health apps start with a login form because their business model requires your email before their product requires your data. Pulsyn starts with a heart rate graph because the app stores everything locally on your phone and has nothing to authenticate against. James Hoffmann Jun 4, 2026 11 min read Read article

What Goes Into Pulsyn's Stress Score James Hoffmann Jun 4, 2026 13 min read

How Pulsyn Calculates Resting Heart Rate (and Why Your Current Number Is Probably Wrong) Most wearables report resting heart rate as the lowest heart rate they can find, usually during sleep. The clinical definition is different. Pulsyn measures it during motionless awake periods, and the gap between the two definitions is often 10 to 15 beats per minute. James Hoffmann Jun 3, 2026 13 min read

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LATEST ARTICLES

A runner on a track at sunset, the exact scenario where smart ring heart rate tracking fails due to finger blood flow physics

Why Smart Rings Are Bad at Workout Tracking, and the Physics of Finger Blood Flow Smart rings promise workout tracking, but the physics of finger blood flow makes PPG nearly useless during exercise. Here is why the heart rate data is often fabricated, and why Pulsyn does not pretend otherwise. James Hoffmann Jun 3, 2026 13 min read

A neon-lit circuit board representing the internal hardware of wearable devices that users are reverse engineering to reclaim their health data

Why People Are Cracking Their Oura Rings A Reddit post called Cracked Oura hit 769 upvotes by showing how to bypass Oura's mandatory subscription using raw BLE data. The thread turned into a product support forum for a product Oura refused to build. James Hoffmann Jun 2, 2026 14 min read

A hotel room at night with an unmade bed, representing the unfamiliar environment where the first night effect occurs and sleep trackers get confused

How Traveling Breaks Your Sleep Tracker (and Why the First Night Effect Is Real) The first night effect is a documented neurological phenomenon where half your brain stays awake in unfamiliar environments. Most wearables treat this as a bad night and tank your score. They should be treating it as a different kind of night entirely. James Hoffmann Jun 1, 2026 11 min read

A close-up of an LED optical sensor circuit board used in biometric wearable devices

How Photoplethysmography Actually Works in a Smart Ring Most smart rings shine light into your finger and count the bounces. The ones that do it well sample at 100 Hz or higher, use green and infrared LEDs in a specific geometry, and process the signal before it ever reaches a server. James Hoffmann Jun 1, 2026 13 min read

A person walking on a forest path, the kind of everyday movement that step counters attempt to measure

What Your Step Count Actually Means and Why 10,000 Is a Marketing Number The 10,000 step goal was invented in 1965 by a Japanese pedometer company. It had no clinical basis then and has only weak evidence now. Most wearables count steps using flawed accelerometer guesswork, which means your 8,000 step day and your friend's 8,000 step day are not the same health outcome. James Hoffmann May 31, 2026 13 min read

A medical stethoscope on a desk with clinical documents, representing the regulatory gap between wellness devices and validated medical equipment

Your Smart Ring Is a Wellness Device, Not a Medical Device. Here's What That Actually Means. The FDA's 19-page general wellness policy lets smart ring companies skip clinical validation entirely. Every wearable you have heard of lives inside that loophole. The difference between wellness and medical is not a matter of degree. It is a matter of whether anyone tested the accuracy before it shipped. James Hoffmann May 31, 2026 12 min read