During a head-up tilt test, women exhibited a delayed and slight increase in sympathetic activity compared to men, who showed an instantaneous and pronounced increase (p<0.05).
Observational (n=29)
Does cardiovascular autonomic regulation during orthostatic challenge differ between healthy men and women?
Healthy women exhibit a more relaxed and delayed sympathetic autonomic response to orthostatic challenge compared to men.
p-value: p=<0.05
Linear dynamic analysis of cardiovascular and respiratory time series was performed in healthy subjects with respect to gender by shifted short-term segments throughout a head-up tilt (HUT) test. Beat-to-beat intervals (BBI), systolic (SYS) and diastolic (DIA) blood pressure and respiratory interval (RESP) time series were acquired in 14 men and 15 women. In time domain (TD), the descending slope of the auto-correlation function (ACF) (BBIₐ31cor) was more pronounced in women than in men (p<0. 05) during the HUT test and considerably steeper (p<0. 01) at the end of orthostatic phase (OP). The index SYSₘeanNN was slightly but significantly lower (p<0. 05) in women during the complete test, while higher respiratory frequency and variability (RESPₛdNN) were found in women (p<0. 05), during 10-20 min after tilt-up. In frequency domain (FD), during baseline (BL), BBI-normalized low frequency (BBILFN) and BBILF/HF were slightly but significantly lower (p<0. 05), while normalized high frequency (BBIHFN) was significantly higher in women. These differences were highly significant from the first 5 min after tilt-up (p<0. 01) and highly significant (p<0. 001) during 10-14 min of OP. Findings revealed that men showed instantaneously a pronounced and sustained increase in sympathetic activity to compensate orthostatism. In women, sympathetic activity was just increased slightly with delayed onset without considerably affecting sympatho-vagal balance.
Reulecke et al. (Wed,) conducted a observational in Healthy subjects (n=29). Female sex vs. Male sex was evaluated on Cardiovascular autonomic regulation (linear dynamic analysis of cardiovascular and respiratory time series) (p=<0.05). During a head-up tilt test, women exhibited a delayed and slight increase in sympathetic activity compared to men, who showed an instantaneous and pronounced increase (p<0.05).