What is SDNN?

SDNN (standard deviation of all normal-to-normal RR intervals) is a comprehensive HRV metric capturing overall autonomic variability over a recording period. It is used in clinical cardiology and long-term stress and health assessments.

What is normalized HRV score (x10)?

Normalized HRV score (×10) is a scaled HRV metric that maps raw HRV values onto a standardized reference range, multiplied by 10 for resolution. It is used by consumer health platforms to present HRV data in a user-friendly numerical format.

Worked examples

1 SDNN = 0.1 normalized HRV score (x10)

1 normalized HRV score (x10) = 10 RMSSD