SDNN stands for the Standard Deviation of NN Intervals. It represents the overall heart rate variability by measuring the standard deviation of all normal-to-normal (NN) intervals in a recording period.

SDNN reflects all the cyclic components responsible for variability in the period of recording, therefore it represents total variability. SDANN (standard deviation of the average NN intervals) calculated over …

Jul 22, 2024 · SDNN (Standard Deviation of NN Intervals) measures overall HRV by calculating the standard deviation of time between normal heartbeats, reflecting both short-term and long-term …

Nov 26, 2025 · SDNN is a time-domain measurement, calculated directly from the time intervals between heartbeats recorded over a defined period. The full name is the Standard Deviation of the …

Aug 25, 2023 · SDNN is a measure of HRV that calculates the average value of HRV in milliseconds and shows how far your HRV is from that average at any point in the day. Although it is often …

The authors reported means, standard deviations, and 95% confidence intervals for 24 h HRV time-domain measures of SDNN, SDANN, SDNN index, RMSSD, and pNN50, and HR by decade.

Dec 1, 2023 · What are HRV score, RMSSD, ln (RMSSD), SDNN and PNN50? Our HRV score is based on RMSSD and represents the strength of your Autonomic Nervous System (specifically the …

Jun 4, 2025 · HRV is one of the most important metrics for understanding your health and fitness, and RMSSD and SDNN are two very useful ways of interpreting this data — for both short-term recovery …

Oct 18, 2022 · When assessed over a 24h period, SDNN is the clinical "gold standard" assessing cardiovascular health and in particular, morbidity and risk of cardiac events. You may also see …

The SDNN is the standard deviation of the normalto- normal (NN) sinus-initiated interbeat-intervals measured in milliseconds. This measure reflects the ebb and flow of all the factors that contribute to …