AccuracyExerciseFitness Tracking
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