Participants will work with a health coach to aim for 7-9 hours of sleep per night, at least 85% sleep efficiency, and less than 60 minutes' variation in bed and wake times.

Participants will work with a health coach focused on enhanced usual care.

This 12-week cognitive behavioral intervention uses motivational interviewing and behavior change principles, focusing on self-efficacy and action planning. Participants target 7-9 hours of sleep per night, ≥85% sleep efficiency, and <60 minutes' variability in bed and wake times.

Components include sleep education and hygiene, nightly routines, the management of competing activities, sleep environment optimization, lifestyle modifications (e.g., avoiding caffeine and vigorous exercise before bedtime), screen time reduction, basic stress management (e.g., progressive muscle relaxation), and self-monitoring. Following a baseline visit, a research assistant conducts a 60-minute telehealth session via HIPAA-compliant Zoom/Teams, with booster sessions at weeks 4, 8, and 12. Sleep time is adjusted weekly based on sleep efficiency criteria.

The multidimensional sleep health composite score assesses six domains: regularity, satisfaction, alertness, timing, efficiency, and duration. Sleep regularity, timing, efficiency, and duration will be measured using a non-dominant wrist-worn research-grade actigraph (Ametris CentrePoint Insight Watch) worn 24/7 during the monitoring period. Sleep satisfaction will be assessed using the global score of the 19-item Pittsburgh Sleep Quality Index (PSQI; range 0-21; scores <5 coded as 1, indicating good sleep). Alertness will be assessed using the Epworth Sleepiness Scale (ESS; range 0-24; scores <8 coded as 1, indicating good daytime alertness). Each component will be scored according to predefined criteria and summed to create a composite score ranging from 0 to 6, with higher scores indicating better overall sleep health over the 1-week monitoring period at each time point. The composite score (unitless) will be assessed at baseline and post-intervention.

HbA1C will be measured by the FDA-approved A1C Now Self-Check. HbA1C reflects the average blood glucose level over the preceding approximately 2-3 months and will be reported as a percentage (%). Changes in glycemia will be assessed by comparing HbA1C values measured at baseline and post intervention. Units = percent (%).

Glucose variability (GV) will be collected using data from the participant's own continuous glucose monitor (CGM) over the 1-week monitoring period at each time point. CGMs provide real-time glucose readings every 5 minutes, offering up to 288 measurements in 24 hours, with high accuracy (test-retest 0.77-0.95). Changes in glucose variability will be assessed by the coefficient of variation (CV) (cv = σ/μ) from baseline to post intervention. Based on the published literature, the 2017 international consensus statement on the use of CGM suggested that 'stable glucose levels are defined as a CV <36% and unstable glucose levels are defined as CV ≥36%. Units = percent (%).