Acute and persistant effects of smoking on the baroreceptor function

1. Recent studies showed that to smoke four cigarettes within one hour impa irs baroreflex sensitivity in humans. In the present study, these effects w ere qualified more precisely from blood pressure and heart rate records by a sequence analysis and by Fourier analysis of Finapres-registrations. 2. The Mayer waves of the heart rate PDS (power density spectrum), partiall y representing sympathetic activity, increased during smoking (83.7 +/- 1.0 AU to 89.5 +/- 1.1 AU, P less than or equal to 0.05) and decreased after s moking (86 +/- 1.0 AU, P less than or equal to 0.05). They did, however, no t reach baseline levels again within 30 min. Probably due to this, mean art erial blood pressure (64.3 +/- 1.3 mmHg vs. 76.9 +/- 1.3 mmHg, P < 0.05) an d heart rate (71.8 +/- 1.4 min(-1) vs. 82.9 +/- 1.4 min(-1), P < 0.05) incr eased unequivocally after smoking. On the other hand, baroreflex sensitivit y decreased dramatically from 15.4 +/- 1 to 11.2 +/- 0.6 ms mmHg(-1) (P < 0 .05). This finding was associated with an increased heart rate variability after smoking (6 +/- 0.5 min(-1) vs. 9.2 +/- 1 min(-1)) 3. Thus, the present study provides evidence that chronic tobacco (nicotine )-abuse causes pathologic alterations of the baroreflex control. In synergi sm with other processes like elevated catecholamine blood levels, these alt erations may contribute to the higher risk of cardiovascular diseases.