Test-retest reliability of time- and frequency-domain measures of short-term resting heart rate variability in a...

Heart rate variability (HRV), the difference in time between successive heart beats, is gaining in popularity among researchers because it is thought to be an effective index of parasympathetic activity. As such, HRV has been associated with individual traits related to mental, emotional, social and physical health outcomes. As it is being used more often as a reflection of relatively stable individual traits, the measurement of HRV's stability was investigated on three time points (T1, T2, T3). A total of 116 participants (i.e., 80 at all time points; 96 at T1 and T2, 89 at T1 and T3, 91 at T2 and T3) completed a survey to assess confounding variables (e.g., sleep quality, exercise behavior, contraceptive use, and consumption of food, recreational drugs, and alcohol) and engaged in a 7-minute seated rest HRV recording to observe ln-RMSSD, HF_peak, ln-HF, and HF_nu. The intraclass correlation coefficients (ICCs) revealed strong correlations for ln-RMSSD and ln-HF._. Reliability analyses were significant but moderate for HF_nu and poor for HF_peak. The measures best thought to reflect vagal tone (RMSSD and ln-HF) did show strong reliability supporting the use of these parameters as a consistent trait-like quality of an individual.