0287 Repetitive Thoughts Linked to Autonomic Dysregulation During Sleep in Older Adult Women

Abstract Introduction Perseverative thought, characterized by negative repetitive thinking such as rumination and worry, is considered maladaptive and has been linked to poor sleep health, autonomic nervous system dysfunction, and elevated cardiovascular disease (CVD) risk. These associations are particularly relevant in the context of sex differences, as insomnia is more prevalent in women, while findings on sex differences in CVD risk in older age remain inconsistent, highlighting the need to identify sex-specific mechanisms underlying these vulnerabilities. Examining how maladaptive cognitive processes before sleep relate to autonomic functioning during sleep may clarify whether these pathways differ for women and men. This study investigated whether pre-sleep rumination and worry, is associated with autonomic function during sleep in older adults, and whether sex moderates this relationship. Methods Sixty-one cognitively healthy older adults (Mage=68.3±4.9 years; 37 women) with no major uncontrolled medical disorders completed the Pre-sleep Arousal Scale–Cognitive subscale (PSAS-cog), assessing cognitive arousal and rumination before sleep, and overnight polysomnography (Sleep Profiler). Moderated regression tested whether PSAS-cog scores interacted with sex in associations with NREM/REM-sleep heart rate (HR) arousal index (brief spontaneous HR changes), controlling for sleep medication use, CVD history, insomnia severity (Insomnia Severity Index), and age. Results The overall model was significant and accounted for ~36% REM sleep HR index variance (R-squared= .361, p<.001). The PSAS-cog×sex interaction term was statistically significant (B=2.16, p=.015). Follow-up conditional effects indicated a significant positive association between pre-sleep cognitive arousal/rumination and REM HR arousal index for women (B=2.54, p<.001), but not men (p=.546). Conclusion The association between pre-sleep perseverative thought and REM sleep autonomic arousal in older adults may be sex-specific. Because the present analyses controlled for insomnia severity, the observed associations may reflect a pathway through which perseverative thought contributes to broader sleep disturbance in older women, independent of clinical insomnia. Future research investigating sex-specific mechanisms, such as declines in circulating estrogen and progesterone during the menopausal transition, which have been shown to affect autonomic regulation, may further illuminate why older women exhibit heightened vulnerability in these pathways. Support (if any) This research was funded by awards (PI:Curtis) from the American Academy of Sleep Medicine Foundation.