0291 ASSOCIATION BETWEEN STRESS-INDUCED AROUSAL AND NOCTURNAL SLEEP

Abstract

Introduction: Stress and hyperarousal contribute to insomnia. Elevated sleep reactivity, characterized by increased sensitivity in physiological stress response and sleep system, might also constitute a vulnerability to hyperarousal and future insomnia. The present study examined acute stress-induced arousal and its impact on sleep. Methods: Participants (26.7 ± 5.3 years; 66.7% female) were adults with insomnia (INS; n=10) and good sleepers (n=20). Based on the Ford Insomnia Response to Stress Test (FIRST=20), good sleepers were further sub-divided into high vulnerability (HV; n=10) and low vulnerability (LV; n=10) to insomnia groups. Participants underwent two nights of polysomnography. On the stress condition night, the Trier Social Stress Test (TSST) was administered. Physiological arousal variables included salivary cortisol, heart rate (HR), heart rate variability (HF, LF/HF ratio), and blood pressure. Subjective arousal was assessed with the Pre-Sleep Arousal Scale. Results: Cortisol, HR, and systolic blood pressure were significantly elevated in response to the TSST in all groups (all ps < .05) and reduced sleep efficiency (ravg=- .41, p< .05). Conclusion: Overall, participants with insomnia showed greater acute cortisol response and (subjective and physiological) bedtime hyperarousal than the LV group but not compared to the HV group. Elevated stress-induced arousal is associated with increased sleep disruptions. These findings support the hyperarousal conceptualization of insomnia and suggest that increased stress reactivity and hyperarousal might represent a trait-like vulnerability in certain good sleepers. More research is warranted to validate and expand our preliminary findings.