Cigarette smoking, stress-induced analgesia and pain perception in men and women

Abstract
This study examined gender differences in smoking-related analgesia and stress-induced analgesia (SIA), as a function of pain modality. Forty men (20 smokers, 20 nonsmokers) and 37 women (17 smokers) were tested twice for pain sensitivity to tourniquet ischemia, thermal heat, and cold pressor tests; once following mental stress and once following rest control, counterbalancing order. Cardiovascular and neuroendocrine responses to mental stress were also examined. While expected gender differences in pain sensitivity were observed, women smokers had greater threshold and tolerance times to ischemic pain than women nonsmokers (PPPP=0.05). Only nonsmokers showed expected inverse relationships between sympathetic and hypothalamic–pituitary–adrenal (HPA) axis reactivity measures and sensitivity to pain. Smokers showed evidence for blunted HPA-axis function at rest and stress. These results indicate that analgesia related to both being a smoker and stress is influenced by gender and pain modality. The reduced pain perception in smokers and absence of relationships between endogenous pain regulatory mechanisms and pain sensitivity may reflect a maladaptive response to chronic smoking.