Patterns of adaptation to stress cardiovascular responses in smokers during ad libitum smoking and withdrawal.

There is considerable evidence documenting associations between tobacco smoking, including initiation, maintenance, and relapse of addiction, with diminished cardiovascular responses to acute psychological stress. However, less is known about how smokers respond to repeated stress across time. The current study examined patterns of cardiovascular reactivity and adaptation to recurrent stress among 24-h abstinence smokers, smokers who continued to smoke at their normal rate, and non-smokers. Smokers were randomly assigned to one of two groups; ad libitum (n = 42), or 24 h abstinence (n = 61); non-smokers (n = 43) provided comparative referencing. Across the two laboratory sessions, participants (n = 149) were asked to complete a modified version of the trier social stress test, while monitoring systolic and diastolic blood pressure, and heart rate activity. Results showed that while non-smokers had elevated cardiovascular reactivity to begin with, they showed a greater capacity to habituate to recurrent stress across sessions. The data also suggest that smokers displayed lower cardiovascular reactivity to acute psychological stress and showed little habituation to repeated stress. In adjusted models, smokers exhibited less systolic blood pressure habituation to stress. This response profile in smokers may be a potential mechanism that leads to further cardiotoxic effects on health.