Objective: To test the hypothesis that heavy smoking is associated with a persistent increase in blood pressure.
Design: In 10 normotensive smokers asked to smoke one cigarette every 15 min for 1 h, blood pressure and heart rate were continuously monitored during the smoking period and during the preceding non-smoking hour. In six other normotensive smokers asked to smoke two cigarettes per hour throughout the whole day, blood pressure and heart rate were monitored non-invasively in ambulatory conditions for 8 h (0900-1700 h). Blood pressure monitoring was repeated during a non-smoking day.
Methods: Beat-to-beat blood pressure and heart rate were monitored at rest by means of the Finapres device. Blood pressure signal was sampled at 165 Hz by a computer to calculate hourly data. Ambulatory blood pressure and heart rate were measured once every 10 min.
Results: In resting conditions, the first cigarette caused an immediate and marked increase in blood pressure and heart rate, and the peak blood pressure and heart rate achieved were similar for the remaining three cigarettes. In each instance, the hemodynamic effects were so prolonged that throughout the smoking hour, blood pressure and heart rate were persistently higher than during the non-smoking hour. The standard deviations of systolic and diastolic blood pressure and heart rate were also higher during the smoking hour, indicating an increase in blood pressure and heart rate variability. In the six ambulant smokers, daytime blood pressure and heart rate were also persistently higher during smoking than during non-smoking.
Conclusions: Heavy smoking is associated with a persistent rise in blood pressure and also with an increase in blood pressure variability. These effects (which may escape clinic blood pressure measurements performed during non-smoking) may account for some of the smoking-related cardiovascular risk.