0675 Sleep Disruption Secondary to Disordered Breathing Directs the Strength Between Physical Activity and Physical Limitations among Dementia Caregivers

Abstract Introduction Sleep-disordered breathing (SDB) increases the risk of cardiovascular diseases and functional limitations. Frequent oxygen disruptions secondary to SDB reduce exercise capacity and limit physical functioning due to fatigue and damage to vasculature that supports mobility. Greater physical activity (PA) is associated with higher functional status, fewer limitations, and a lower risk of SDB. Modifiable risk factors, including sedentary lifestyles and poor sleep, provide preventative opportunities to improve and sustain physical functioning, especially among dementia caregivers (CGs) at increased risk of poor health outcomes and physical disability. We examined how the frequency of SDB influences the relationship between PA and physical limitations among CGs with insomnia. While RDI has an inverse relationship with PA and physical functioning, its influence on the association between PA and physical functioning is complex and not well understood among CGs with insomnia. Methods CGs (N=69; Mage=56, F=75.8%) with insomnia in an RCT (NIH R01AG066081, NCT04896775) reported at baseline weekly PA (Godlin-Shephard Leisure-Time questionnaire) and general/physical functioning (36-Item Short Form Health Survey, SF-36). They completed 1-night WatchPAT One home sleep testing (Manufacturer; RDI [(>5 vs < 5 SDB events/hr]). Moderation analysis with SPSS Process Macro examined the relationships between total weekly PA, general & physical functioning, and RDI group (moderator). Results Moderation analysis showed a trending interaction between weekly PA and RDI group (B=-0.16, SE=0.08, t=-2.0, p=0.05), with a higher RDI group showing a weaker effect of PA on physical limitations. The relationship between PA and number of SDB events was positive and significant for participants with < 5 events (B=0.23, SE=0.07, t=3.13, p=0.0026) and for those with >5 events (B=0.07, SE=0.03, t=2.26, p=0.02). The overall model explained 18.69% of the variance in physical functional limitations (F [3,65] = 4.98, p=0.0036). Conclusion Among dementia caregivers with insomnia, the association between physical activity and physical functioning weakens as disordered breathing events increase. Given the physical functioning measure assessed limitations across various mobility activities, further examination of specific activities—such as vigorous exercise versus walking a block—could reveal which functions are most affected by frequent disordered breathing events. This could lead to future interventions aimed at reducing the risk of disability. Support (if any)