Stability over time of variables measuring heart rate variability in normal subjects

Effects of trans- and n-3 unsaturated fatty acids on cardiovascular risk markers in healthy males. An 8 weeks dietary intervention study

“…A positive effect on HRV was observed in all groups, possibly due to increased attention to physical health during the study period. However, also at baseline our group of healthy men showed a very high HRV compared to other studies of normal men (Kleiger et al, 1991). It is therefore of interest that in the subgroup analysis, after excluding the 25% of the men with the highest HRV at baseline and leaving the men with a mean SDNN of 156 ms, a value which is comparable to previous reported SDNN data for normal men (Kleiger et al, 1991), an increase in 24-h heart rate ( ¼ decreased RR) was found in the TFA group contrasting to an increase in RR in the other groups.…”

Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

“…Thus, studies carried out on healthy individuals have shown good reproducibility of temporal parameters when www.bjournal.com.br Braz J Med Biol Res 43(10) 2010 records were obtained within short (<24 h) and long (>24 h) recording periods (18,20,21,26). However, even with long recordings, reproducibility has been questioned in relation to spectral parameters (22,(27)(28)(29).…”

“…Previous studies on intra-indivudual reproducibility of HRV have been conducted with subjects in the classical supine position (17,22,26). Since this exam sometimes is also carried out during postural maneuver (tilt-test for example), we compared the reproducibility of temporal and spectral HRV indexes of a group of healthy individuals in the supine and orthostatic positions using short-term recording periods under spontaneous breathing.…”

Heart rate variability and critical flicker fusion frequency changes during and after parachute jumping in experienced skydivers

“…RMSSD and pNN50 are recognised indexes of parasympathetic activity (Task force 1996; Kleiger et al 1991;Manfrini et al 2003) and pNN50 might be useful in clinical practice as it shows a strong relation with the later occurrence of coronary events (Manfrini et al 2003). …”

“…In the past decades non-invasive techniques based on heart rate variability (HRV) have been used as markers of autonomic modulation of the heart (Stein et al 1994;van Ravenswaaij-Arts et al 1993;Sztajzel 2004). A few studies which have addressed the clinical significance of linear and non-linear analysis of HRV tell us about a potential cardiovascular risk associated with the dominance of one of the branches of the ANS (Goseki et al 1994;Krstacic et al 2007;Kleiger et al 1991). It is then paramount to further explore this ANS modulation in experienced, rather than novice, skydivers to enhance our understanding of the cardiovascular dynamics to skydiving.…”