Older age was associated with delayed time to peak decrease in heart rate (3.8 vs 2.1 s) and mean blood pressure (8.3 vs 6.7 s) during carotid baroreceptor loading compared to young subjects (P<0.05).
Cross-Sectional
Does ageing delay the peak cardiovascular response to acute carotid baroreceptor loading in humans?
Ageing is associated with delayed peak cardiovascular responses to acute carotid baroreceptor loading, which may be partly driven by age-related reductions in cardiac parasympathetic tone.
Absolute Event Rate: 3.8% vs 2.1%
p-value: p=< 0.05
The stability of a physiological control system, such as the arterial baroreflex, depends critically upon both the magnitude (i.e. gain or sensitivity) and timing (i.e. latency) of the effector response. Although studies have examined resting arterial baroreflex sensitivity in older subjects, little attention has been given to the influence of ageing on the latency of peak baroreflex responses. First, we compared the temporal pattern of heart rate (HR) and mean arterial blood pressure (BP) responses to selective carotid baroreceptor (CBR) unloading and loading in 14 young (22 +/- 1 years) and older (61 +/- 1 years) subjects, using 5 s pulses of neck pressure (NP, +35 Torr) and neck suction (NS, -80 Torr). Second, CBR latency was assessed following pharmacological blockade of cardiac parasympathetic nerve activity in eight young subjects, to better understand how known age-related reductions in parasympathetic nerve activity influence CBR response latency. In response to NP, the time to the peak increase in HR and mean BP were similar in young and older groups. In contrast, in response to NS the time to peak decrease in HR (2.1 +/- 0.2 vs. 3.8 +/- 0.2 s) and mean BP (6.7 +/- 0.4 vs. 8.3 +/- 0.2 s) were delayed in older individuals (young vs. older, P < 0.05). The time to peak HR and mean BP were delayed in young subjects following cardiac parasympathetic blockade (glycopyrrolate). Collectively, these data suggest that ageing is associated with delayed peak cardiovascular responses to acute carotid baroreceptor loading that may be, in part, due to age-related reductions in cardiac parasympathetic tone.
Fisher et al. (Tue,) reported a cross-sectional. Ageing vs. Young subjects was evaluated on Time to peak decrease in heart rate in response to neck suction (seconds) (p=< 0.05). Older age was associated with delayed time to peak decrease in heart rate (3.8 vs 2.1 s) and mean blood pressure (8.3 vs 6.7 s) during carotid baroreceptor loading compared to young subjects (P<0.05).