Sleep Architecture and Efficiency in Older Adults: A Clinical Analysis in the Context of Obstructive Sleep Apnea<br>—How Aging Shapes Sleep: A Closer Look at Sleep Architecture and Efficiency in Older Adults with Suspected Sleep Apnea

Introduction: Obstructive sleep apnea (OSA) is highly prevalent among older adults and is often accompanied by increased sleep fragmentation and progressive deterioration of both deep (N3) and REM sleep. Despite its impact on functional capacity and cardiovascular risk, detailed descriptions of sleep architecture in this population remain limited—especially in Latin American cohorts. This study aims to analyze polysomnographic characteristics and sleep fragmentation in a geriatric cohort with suspected OSA from Colombia’s Caribbean region, focusing on the proportion of N3 sleep as a potential functional marker. Methods: This was a prospective cross-sectional study based on a consecutive cohort of older adults (≥60 years) who underwent full-night attended polysomnography (Type I) between August 2023 and March 2025. Clinical, anthropometric, and polysomnographic variables were collected. Descriptive and comparative analyses were performed according to sex, age group (60 - 69 vs. ≥70 years), OSA severity, and proportion of N3 sleep (Results: A total of 129 patients were included. Mean age was (69.8 ± 6.5) years, with a male predominance (60.5%). Moderate to severe OSA was observed in 79.8% of the cohort. Patients aged ≥70 showed significantly lower proportions of N3 and REM sleep, and higher proportions of N1 sleep and microarousals. Women exhibited greater sleep fragmentation and reduced deep sleep. Age positively correlated with microarousal index (r = 0.34). Multivariate regression analysis showed a negative trend between age and N3 sleep (β = −0.17; p = 0.077). Those with Conclusion: In older adults from Colombia’s Caribbean coast with suspected OSA, sleep architecture shows significant alterations not fully explained by AHI alone. The progressive fragmentation and loss of deep sleep observed in older and more severe OSA subgroups may serve as functional indicators of physiological decline in geriatric care. These findings highlight the need to incorporate structural sleep variables—such as N3 proportion and microarousal index—into the comprehensive clinical assessment of OSA in older adults.