Dynamic cerebral autoregulation after acute cigarette smoking in non‐smokers and habitual smokers

Abstract

IntroductionCigarette smoking is associated with an increased risk of stroke in a dose dependent manner. Impaired baroreceptor function, associated with hypertension and increased blood pressure (BP) variability, offers one potential mechanism for smoking‐induced stroke risk. However, studies to date have not assessed whether smoking impairs dynamic cerebral autoregulation (dCA) or the interplay between dCA and baroreflex function in smokers. Thus, this study examined the impact of acute and chronic cigarette smoking on dCA and baroreflex function.MethodsWe recruited 17 non‐smokers and 15 habitual smokers. Transfer function analysis was used to examine dCA and baroreflex sensitivity before and immediately after acute smoking (a single cigarette) during spontaneous breathing.ResultsThere were no between‐group differences in dCA metrics (gain, phase and coherence) or low frequency baroreflex gain at baseline. However, both groups, showed a decrease in transfer function gain and coherence and increase in phase, after acute smoking, suggesting improved dCA. This increase in dCA was accompanied by a reduction in baroreflex gain, and increase in BP variability.ConclusionThese novel findings suggest that an increase in dCA counteracts the impact of impaired baroreflex function, potentially buffering the delicate cerebral vessels from the increase in BP variability after acute smoking.