Selective cardiovascular effects of stress and cigarette smoking.

The purpose of the present study was to determine how cigarette smoking and psychological stress combine to affect cardiovascular function. Stress was operationally defined as playing a series of difficult video games under challenging instructional conditions. Following an initial test game, 51 smokers were randomly assigned to a 2 (smoke vs. sham smoke) X 2 (stress vs. no stress) design. The results showed that the subjects who sham smoked (inhaled unlit cigarettes) under no stress evidenced minimal changes in cardiovascular parameters. Subjects who smoked under no stress evidenced approximately 12 mmHg increase in systolic blood pressure (SBP) and 9 mmHg increases in diastolic blood pressure (DBP), and a 15 beat-per-minute increase in heart rate (HR). These effects were similar in magnitude to those seen in subjects who sham smoked under stress. By contrast, subjects who smoked under stress showed markedly larger increases in all cardiovascular parameters, approximately doubling the magnitude of the observed response over that seen with either smoking or stress alone. Correlational analyses suggested the presence of stable individual differences in autonomic lability or sensitivity. Possible mechanisms are suggested whereby stress and smoking may combine to heighten the risk for coronary disease.