RMSSD, SDNN, LnRMSSD — your wearable picks one and doesn't tell you which. Here's what HRV actually measures, how Oura, Garmin, WHOOP, and Polar each capture it differently, and why your baseline matters more than any single number.
Bevel is a polished health dashboard with Oura and Garmin support. But if you want validated nutrition data, transparent scoring, or cross-domain correlations backed by statistics — here's what else is out there.
We reviewed 17 peer-reviewed studies comparing Oura, Apple Watch, Fitbit, Garmin, WHOOP, and Samsung across sleep, heart rate, HRV, SpO2, VO2 max, and more. Here are the specific numbers.