0304 EVIDENCE OF BLUNTED PHYSIOLOGICAL RESPONSES TO ACUTE STRESS IN WOMEN WITH INSOMNIA IN THE MENOPAUSAL TRANSITION

Abstract

Introduction: Stress is a well-recognized factor implicated in the pathophysiology of insomnia; however, it is unknown whether women with insomnia developed in the context of the menopausal transition have altered stress responses. Methods: We investigated cortisol and cardiac autonomic responses to an acute experimental stress (Trier Social Stress Task, TSST) in perimenopausal women with (n = 22, age: 50.95 ± 2.82 years) and without (n = 16, age: 48.81 ± 3.12 years) insomnia. After a night in the laboratory, participants completed the TSST, a well-established psychosocial stress protocol. Electrocardiograph was continuously recorded and saliva was taken at intermittent intervals before and after the task for cortisol analysis. Participants were tested in the luteal phase of the menstrual cycle if they were still cycling or on a random day if they had unpredictable cycles; progesterone was used as a covariate. Results: There were no group differences in task-related perceived stress or in the cortisol stress responses. Women with insomnia showed a smaller increase in heart rate (HR) (i.e. smaller HR reactivity, p=0.02), associated with a smaller drop in total heart rate variability (p=0.006) during the speech task, compared with controls. HR during baseline and recovery did not differ between groups. Progesterone was a significant factor in HR models, with higher HR associated with higher progesterone during the stress task (p=0.038), although progesterone was not a significant factor for task reactivity. Stress exposure was associated with one or more physiological hot flashes in a portion of women symptomatic for hot flashes. Conclusion: Women with insomnia that developed in the menopausal transition have blunted cardiac activation in response to an acute stressor, suggesting altered physiological reactivity to stress. This altered autonomic function might be pre-existing or developed as a consequence of sleep disruption and/or other symptoms in the menopausal transition.