Associations of trait optimism with diurnal neuroendocrine activity, cortisol responses to mental stress, and subjective stress measures in healthy men and women.

OBJECTIVE: To examine the associations of dispositional optimism with diurnal salivary cortisol, cortisol responses to standardized laboratory stress, and task-induced subjective stress and control in a sample of individuals 53 years and older.
METHODS: Five hundred forty-three healthy men and women (mean [standard deviation] age, 62.9 [5.7] years) attended a psychophysiological stress session and provided five salivary cortisol samples during a normal day. During the stress testing session, cortisol responses to two behavioral tasks were assessed. The associations of dispositional optimism with cortisol and subjective appraisal were assessed using hierarchical multiple regression analysis.
RESULTS: The cortisol awakening response, but not the diurnal profile, was negatively associated with optimism independently of age, sex, employment grade, body mass index, smoking status, depressive symptoms, and time of awakening (β = -0.12, p ≤ .05). No associations were observed between optimism and stress-induced cortisol changes in the laboratory; however, perceived stress was lower (β = -0.18, p ≤ .001), and perception of control was higher (β = 0.18, p ≤ .001), in more optimistic participants during the psychophysiological testing session.
CONCLUSIONS: Dispositional optimism may confer benefits to the individual through attenuated hypothalamic-pituitary-adrenal axis response to waking in everyday life. However, no evidence emerged for an association between optimism and cortisol laboratory stress responses, which suggests that other compensatory mechanisms might play a role.