RELATIONSHIP BETWEEN CHRONIC SLEEP RESTRICTION (<6 HOURS/NIGHT) AND GLYCEMIC VARIABILITY IN WORKING ADULTS WITH TYPE 2 DIABETES: A SYSTEMATIC REVIEW

Background: Chronic sleep restriction is increasingly recognized as a contributor to impaired glucose regulation, yet its effect on day-to-day glycemic instability remains incompletely defined. Working adults with type 2 diabetes mellitus are especially vulnerable because shift work, extended schedules, occupational stress, and irregular sleep timing may compound insulin resistance. Continuous glucose monitoring offers a more sensitive assessment of these effects than glycated hemoglobin alone by capturing glucose excursions, nocturnal instability, and time spent within target ranges. Objective: To evaluate the association between chronic sleep restriction of fewer than six hours nightly and glycemic variability among working adults with type 2 diabetes mellitus. Methods: This PRISMA-guided review searched PubMed, Scopus, Web of Science, Embase, and Google Scholar for English-language peer-reviewed studies published from 2010 to 2025. Eligible studies examined working adults with type 2 diabetes mellitus, short sleep or occupational sleep disruption, and continuous glucose monitoring-derived or related glycemic outcomes. Screening, standardized extraction, and design-appropriate risk-of-bias assessment were completed. Methodological heterogeneity required narrative synthesis. Results: Of 419 records identified, 13 studies involving 1,200 participants were included. Individual samples ranged from 19 to 210 participants, and the studies represented 10 countries. Twelve studies reported adverse associations between restricted or disrupted sleep and glycemic outcomes. Sleep-restricted participants generally showed higher mean amplitude of glycemic excursions and coefficient of variation, lower time in range, elevated glycated hemoglobin, increased nocturnal and fasting glucose fluctuations, reduced insulin sensitivity, and impaired glucose tolerance. Shift workers and employees exposed to occupational stress showed less stable glucose profiles. Conclusion: Chronic sleep restriction was consistently associated with poorer glycemic stability among working adults with type 2 diabetes mellitus. Sleep duration and work schedules should be assessed in diabetes care, while longitudinal and interventional studies are needed to clarify causality and clinical benefit. Keywords: Blood Glucose; Circadian Rhythm; Continuous Glucose Monitoring; Diabetes Mellitus, Type 2; Occupational Stress; Shift Work Schedule; Sleep Deprivation.