Young Trauma-Exposed Women with Low Sleep Effciency have Blunted Sympathetic Baroreflex Sensitivity and Higher Muscle Sympathetic Nerve Activity

Abstract

Introduction: Poor sleep, a known risk factor for cardiovascular disease (CVD) and one of the American Heart Association’s essential 8th, is common after trauma-exposure. Although premenopausal women are thought to be protected from CVD, trauma exposure might increase their CVD risk. In a recent large epidemiological study examining sleep-related CVD comorbidities, the empirical cut off point for optimal sleep effciency (SE) was set at 83%, distinguishing between good and poor sleep effciency. Studies have suggested an overactive sympathetic nervous system and an impaired baroreflex sensitivity (BRS) as potential mechanisms of increased CVD risk. However, the impact of poor sleep effciency on muscle sympathetic nerve activity (MSNA) and BRS in young trauma-exposed women is unknown. We hypothesized that young trauma-exposed women with poor sleep effciency will present with impaired BRS and increased MSNA at rest. Methods: We collected data on 30 women (18 – 40 years) from diverse backgrounds who had been exposed to trauma. Sleep data was acquired via ActiWatch for 7 days and used to categorize our participants into two groups: good effciency (SE > 83%, n=17) and poor effciency (SE < 83%, n=13), with SE calculated as the percentage of time spent asleep while in bed. Additionally, we collected continuous noninvasive blood pressure (BP), heart rate (HR), and MSNA (burst frequency, incidence, and total activity) during 10 minutes of quiet rest. Sympathetic BRS was determined as the slope of the regression between individual sympathetic bursts and diastolic BP bins (3 mmHg), weighted against the number of cardiac cycles, utilizing an automated program (Ensemble, NZ). Results: There were no significant differences in trauma symptom severity, resting BP and HR between the two groups (p>0.05 for all). However, resting sympathetic BRS was blunted in the poor SE (-0.10±0.88 bursts/100hb/mmHg) compared to the good SE (-1.44±1.58 bursts/100hb/mmHg, p=0.006) group, even after adjusting for age (p=0.009). Likewise, resting total MSNA was higher in the poor SE compared to the good SE after adjusting for age (p=0.028). MSNA burst frequency and burst incidence were comparable between the groups (p>0.05). Conclusion: Our analyses revealed that poor sleep effciency is associated with decreased sympathetic baroreflex sensitivity and higher total muscle sympathetic activity at rest, regardless of age. Blunted sympathetic BRS may contribute to increased sympathetic activity in young women with poor sleep effciency. Future studies testing strategies to improve sleep effciency in this population could provide potential long-term cardiovascular benefits. UL1TR002494 and NIH K01HL161027 No disclosure. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.