"Paradoxical" effects of smoking on subjective stress versus cardiovascular arousal in males and females.

Cigarette smoking has sometimes been found to decrease subjective stress while simultaneously increasing cardiovascular arousal, contrasting effects referred to as the "nicotine paradox." The present study assessed acute effects of cigarette smoking on subjective stress vs. cardiovascular arousal in minimally deprived male and female smokers who smoked (n = 16) or sham smoked (unlit cigarette, n = 15) and a comparison group of male and female nonsmokers (n = 12) who sham smoked only. All subjects participated in two sessions (high- or low-challenge computer task) in which they smoked or sham smoked prior to each of two 20-min task trials. Results showed reduced subjective stress in smoking smokers compared with sham-smoking smokers during the high- but not low-challenge task. However, this stress reduction occurred only immediately after smoking and dissipated midway through each trial. In males, smoking appeared to reduce stress below that of nonsmokers, while smoking in females attenuated stress only partially to the level of nonsmokers. In contrast with the attenuated stress effects, cardiovascular arousal (especially heart rate) was increased immediately after smoking during both tasks and did not appear to be directly related to subjective changes. These findings suggest that the stress-reducing effects of smoking may be transient, situationally specific, partly gender dependent, and dissociated from the effects of smoking on cardiovascular arousal.