Abstrato

Effects of age and sex on vasomotor activity and baroreflex sensitivity: difference between wakefulness and sleep

Chia-Hsin Yeh, Terry B. J. Kuo, Jia-Yi Li, Kuan-Liang Kuo, Chang-Ming Chern, Cheryl C. H. Yang, Hsin-Yi Huang

Background: Cardiovascular function is related to age, sex, and consciousness state, yet age and sex differences in Baroreflex Sensitivity (BRS) during the sleep–wake cycle in individuals aged 20–79 years remain unclear. This study investigated sex and sleep-stage-related differences in the BRS pattern among different age groups.

Methods: Sixty-seven healthy participants (aged 20-79 years; 41 women) were divided into four groups according to age: 20-29, 30-49, 50-69, and 70-79 years. Laboratory polysomnography and blood pressure recordings were collected from all participants. Spontaneous BRS was estimated from Arterial Pressure–R-R Interval (AP-RR) transfer function and linear regression; arterial pressure variability, Heart Rate Variability (HRV), and BRS parameters during sleep–wake stages were averaged for each participant. Parameters were analyzed across the four groups.

Results: Both BRS and HRV were significantly negatively correlated with age, while BRS had a stronger relationship with age than HRV did. Only BRS demonstrated a significantly negative correlation with age in the 50-79 year-old group. Compared with men, women exhibited a stronger association between BRS and age and a decline in BRS earlier in life. This decline in women demonstrated different patterns before and after the age of 50 years; BRS heterogeneity increased at approximately 50 years of age.

Conclusions: In the present study, changes in BRS were found to vary with age, sex, and consciousness state, with each showing a specific pattern. The age of 50 years appeared to be a crucial turning point for sexual dimorphism in BRS.