Arterial Pressure, Heart Rate, and Cerebral Hemodynamics Across the Adult Life Span

Abstract

Age-related alterations in systemic and cerebral hemodynamics are not well understood. The purpose of this study is to characterize age-related alterations in beat-to-beat oscillations in arterial blood pressure (BP), heart rate (HR), cerebral blood flow (CBF), cardiac baroreflex sensitivity (BRS) and dynamic cerebral autoregulation (dCA) across the adult life span. We studied 136 healthy adults aged 21–80 years (60% women). Beat-to-beat BP, HR and CBF velocity were measured at rest and during sit-stand maneuvers to mimic effects of postural changes on BP and CBF. Transfer function analysis was used to assess BRS and dCA. Carotid-femoral pulse wave velocity (cfPWV) was measured to assess central arterial stiffness. Advanced aging was associated with elevated cfPWV, systolic and pulse BP, cerebrovascular resistance and CBF pulsatility, but reduced mean CBF velocity. Compared to the young and middle-aged, older adults had lower beat-to-beat BP, HR and CBF variability in the low frequency ranges (LF) at rest, but higher BP and CBF variability during sit-stand maneuvers. BRS was reduced, while dCA gain was elevated at rest in older adults. Multiple linear regression analysis indicated that systolic BP variability is correlated positively with cfPWV independent of HR variability. In conclusion, advanced aging is associated with elevated pulsatility in BP and CBF, reduced beat-to-beat LF oscillations in BP, HR and CBF, and impaired BRS and dCA at rest. The augmented BP and CBF variability in older adults during sit-stand maneuvers indicate diminished cardiovascular regulatory capability and increased hemodynamic stress on the cerebral circulation with aging.

Dynamic cerebral autoregulation is attenuated in young fit women

“…In a population ranging in age from 21 to 80 years old, Xing et al. () reported lower VLF gain and higher phase during 0.05 Hz repeated squat‐stand maneuvers as compared with men, again suggesting a better dCA in women. In contrast to this investigation, Patel et al.…”

“…; Xing et al. ) compared to age‐matched men. Of note, older women present less orthostatic symptoms or syncope than their younger counterparts (Romme et al.…”

Cerebral blood flow in normal aging adults: cardiovascular determinants, clinical implications, and aerobic fitness

“…In both conditions, heart rate variability was substantially reduced and cardiovagal baroreflex sensitivity was significantly attenuated in older adults compared with young adults (Xing et al . ). We also observed that low frequency CA gain is inversely correlated with the baroreflex gain in young subjects, as reported from a previous study (Tzeng et al .…”

“…Furthermore, augmented BP and CBF variability during repeated sit‐stand maneuvers indicate diminished cardiovascular regulatory capability in older adults and increased hemodynamic stress on the cerebral circulation with advanced aging (Xing et al . ).…”

Blood pressure management in older people: balancing the risks

“…In general, a brachial mean BP ≥60 mm Hg is thought to afford an adequate cerebral blood flow. Cerebral blood flow autoregulation may be affected in advanced age,49 by endotheliopathy, hypertension, diabetes mellitus,50 heart failure,51 hypocapnia, alkalosis, sympathetic arousal, autonomic failure,52 early after head injury, during an acute ischaemic stroke or during sepsis 53. The cerebral flow reserve also depends on the existence of cerebral small and large artery disease.…”