Heart rate variability, Reliability, Autonomic nervous system, Test-retest, Orthoclinostatic

Heart rate variability (HRV) has been increasingly analysed under numerous research settings. HRV measurement reliability is, however, still an unresolved issue. The main purpose is to carry out an intra-session stability evaluation of HRV parameters from short-term recordings by means of orthoclinostatic stimulation in a study group which is stratified by gender or Total Power (PT) magnitude. The goal is to make as homogeneous a study group as possible and investigate whether the reproducibility level could be influenced by these factors. There are not any significant differences in absolute or relative reliability between the more homogeneous study groups and we have therefore concluded that HRV measurement reliability is not influenced by gender or HRV magnitude.