Effect of smoking cessation and relapse on cardiovascular levels and reactivity.

This study was designed to investigate the effect of smoking cessation on heart rate, blood pressure, and finger temperature absolute levels and reactivity to a range of laboratory challenges. The 148 quitters (mean age = 43.3 years, mean amount smoked = 24.9 cigarettes per day, mean years smoked = 25.2) completed three assessments: an average of 4 +/- 2.8 days before cessation (Exam 1), an average of 2 +/- 1.0 days after cessation (Exam 2), and an average of 20 +/- 5.5 days after cessation (Exam 3). A nonsmoking group (n = 39) was similarly assessed three times to control for effects related to repeated testing. Comparison of group changes from Exam 1 to Exam 2 indicated that smoking cessation produced a significant decrease in heart rate during rest and during all stressors (mean = -8.9 bpm). Those quitters who remained abstinent or smoked occasionally showed minimal changes in heart rate from Exam 2 to Exam 3, but those quitters who returned to their previous smoking level showed a significant increase in heart rate from Exam 2 to Exam 3. None of the indices of cardiovascular reactivity changed across exams, and neither did absolute levels of blood pressure or finger temperature at rest or during stressors. The possible mechanisms producing a selective heart rate decline after smoking cessation in the absence of pressor or vasodilation effects are discussed.