A. Adan et M. Sanchezturet, SMOKING EFFECTS ON DIURNAL-VARIATIONS OF CARDIOVASCULAR PARAMETERS, International journal of psychophysiology, 20(3), 1995, pp. 189-198
Previous studies have reported that nicotine increases heart rate and
blood pressure, showing a peak 10 min after intake. But most of the wo
rk has focused on the period of maximum effect on cardiovascular param
eters and has been limited to morning measurements, The aim of this st
udy is to evaluate the effects of smoking in diurnal variations of hea
rt rate and blood pressure, when no restrictions are placed on the pat
tern of consumption and activity is controlled. The sample consisted o
f healthy subjects, 21 smokers and 21 non-smokers, from 18 to 26 years
. The recordings were carried out hourly from 8:00 to 21:00 h in resti
ng conditions. Heart rate was measured beat-to-beat for 2 min, and blo
od pressure was assessed by a conventional electronic monitor. Smokers
and non-smokers did not differ in diurnal levels of heart rate nor bl
ood pressure when time of day was not considered. However, when time o
f day was taken into account, the groups differed significantly for he
art rate and systolic blood pressure, while diastolic blood pressure o
nly showed differences for post-lunch period. The influence of nicotin
e on the cardiovascular system of young and healthy smokers is more ap
parent in the diurnal variations than in the mean level of heart rate
and blood pressure. The results emphasize the importance of a chronobi
ological approach in the study of the early stages of smoking on cardi
ovascular parameters.