0162 Mental Stress Compromises Human Sleep Through a Biological, Not Psychological, Pathway

Abstract

Abstract Introduction The extent to which mental stress causes sleep disturbance is unknown as experimental studies of stress and sleep have yielded mixed results. Potential mechanisms linking stress to poor sleep are also poorly characterized. The current study aimed to 1) assess the impact of experimentally-induced mental stress on daytime sleep and 2) test candidate mechanisms including physiological and emotional stress reactivity, stress rumination, attentional threat bias, and insensitivity to future consequences. Methods Participants (N=30) were randomized to a control (n=14) or stress group (n=16). Both groups were given a 60-minute nap opportunity at midday (≈13:30). Prior to sleep, participants in the stress group completed a socially evaluative mental arithmetic stress task and were instructed that they would be required to give a brief speech upon awakening. Sleep was monitored with polysomnography and scored according to standard AASM criteria. Measures of heart rate (HR), blood pressure (BP) and self-reported stress were recorded during the stress task. Self-reported stress rumination was measured upon awakening. Attentional threat bias was measured using an emotional dot probe and performance on the Iowa Gambling Task quantified insensitivity to future consequences. Results Acute mental stress significantly increased HR and BP (all p<.001, all Cohen’s d>1.24) and participants reported significant increases in self-reported stress (p<.001). The stress group exhibited longer sleep latency (p=.038, d=.82), shorter sleep duration (p=.044, d=.78), and worse sleep continuity (p=.045, d=.79). Subjective sleep quality was not different across groups (p=.39, d=.32). Of all candidate mechanisms, physiological reactivity was the only one significantly related to sleep measures. Greater HR reactivity predicted longer sleep latency (r=.37), shorter sleep duration (r=-.59), and worse sleep continuity (r=-.59). Conclusion Acute mental stress caused significant disturbances in a single episode of daytime sleep. The degree of disturbance was, to an extent, predicted by the amount of physiological reactivity to stress. Support This work was supported a Washington and Lee University Summer Lenfest Grant and the Summer Research Scholars Program.