What a Health Wearable Can Actually Tell You, and Where It Guesses
A wearable’s heart rate reading and its sleep stage breakdown are not equally trustworthy, and treating them the same way is the actual mistake.
sleep tracking accuracy
Sleep Tracking Apps and Wearables 2026: What They Measure, What They Get Wrong, and What to Actually Use
Every major wearable now tracks sleep, but the algorithms differ widely.