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Acute effects of smoking on blood pressure and cerebral blood flow
J M Cruickshank1, G Neil-Dwyer, D E Dorrance
1Imperial Chemical Industries plc, ICI Pharmaceuticals, Macclesfield, Cheshire, UK.
Insights
Smoking cigarettes acutely raises heart rate, blood pressure, and middle cerebral artery velocity while significantly decreasing cerebral blood flow (CBF). These effects may be linked to nicotine and have clinical implications for high-risk individuals.
Area of Science:
- Neurology
- Cardiovascular Physiology
- Toxicology
Background:
- Chronic smoking is linked to increased stroke risk and reduced cerebral blood flow (CBF).
- The immediate impact of smoking on CBF remains unclear, especially in relation to hemodynamic changes.
Purpose of the Study:
- To investigate the acute effects of smoking on heart rate, blood pressure (BP), and CBF.
- To assess changes in middle cerebral artery flow velocities during acute smoking.
Main Methods:
- Six healthy volunteers smoked three cigarettes with 2-hour intervals.
- Cerebral blood flow (CBF) was measured using xenon inhalation.
- Middle cerebral artery flow velocities were assessed via transcranial Doppler ultrasound.
Main Results:
- Smoking induced significant increases in heart rate, BP, and middle cerebral artery flow velocities.
- A significant reduction in hemispheric cerebral blood flow (CBF) was observed, with individual falls up to 40% developed.
- These hemodynamic changes are likely mediated by nicotine-induced catecholamine release.
Conclusions:
- Acute smoking causes significant hemodynamic alterations, including reduced CBF and increased BP.
- The findings highlight potential risks of acute smoking, particularly for individuals with pre-existing cardiovascular conditions like hypertension.
Abstract:
Chronic smoking, particularly in hypertensives, is associated with an increased frequency of cerebral infarction and subarachnoid haemorrhage; cerebral blood flow (CBF) is also decreased in chronic smokers. The acute effects of smoking upon CBF are less clear. The present study in six volunteers investigated the immediate effects of smoking (and inhaling) three cigarettes, each separated by a 2 hr gap, upon heart rate, blood pressure (BP) and CBF assessed by xenon inhalation and flow velocities in the middle cerebral artery by transcranial Doppler ultrasound. Smoking caused significant increases in heart rate, BP and middle cerebral artery flow velocities, and a significant fall in CBF (individual falls in hemispherical flow could be as great as 40%). These haemodynamic effects are probably caused by nicotine-induced changes in catecholamine release. The possible clinical significance of the BP and CBF changes induced by acute smoking in high-risk groups is discussed.