Cardiovascular autonomic reflexes in heavy smokers.
In order to study the effect of smoking on cardiovascular function, 25 healthy subjects with an average smoking history of 25 +/- 9 pack-years were examined using the Valsalva manoeuvre and the deep-breathing test. For each smoker there was a healthy, non-smoking control subject of matching age, sex and body mass index. During the tests, heart rate and blood pressure were recorded continuously. Compared with the controls, the smokers had (1) a smaller increase in heart rate during the strain phase of the Valsalva manoeuvre (P = 0.04); (2) weaker rebound increases in arterial pressure after the Valsalva strain (P = 0.007 for systolic and P = 0.02 for diastolic blood pressure); (3) smaller reflex bradycardia after the Valsalva strain (P = 0.02); and (4) a longer latency between post-strain rises in pressure and bradycardia (P = 0.001). This suggests that diminished blood pressure responses occur as a consequence a chronic dysregulation of peripheral vasoconstriction, while diminished heart rate responses are due to attenuated blood pressure responses. A prolonged latency may be a sign of a dysfunction of parasympathetic baroreflex control. It is concluded that heavy smoking is accompanied by a disturbance of cardiovascular autonomic control.
Social Insurance Institution, Rehabilitation Services, Turku, Finland.
S J
SJ
Piha
D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012018:Reflex / Q000502:physiology*; D012907:Smoking