Sleep Schedule Consistency

The Sleep Regularity Index was the sleep parameter most broadly associated with clinical outcomes, linking to NYHA class, frailty, ADL independence, and all KCCQ-12 subscales except overall quality of life. Individuals with regular sleep schedules have significantly lower risk of cardiovascular disease. Consistency in the sleep-wake schedule is the foundation of good circadian health for night shift workers. Among quality-of-life domains, the SRI's predictive strength was greatest for social limitation, followed by physical limitation and symptom frequency. Sleep schedule consistency provides cardiovascular benefits independent of total sleep duration, sleep fragmentation, and obstructive sleep apnea. Sleep irregularity is the most clinically significant dimension of sleep disturbance in heart failure, spanning associations with symptom load, frailty, functional independence, and quality of life. Maintaining consistent sleep times may be equally or more critical than sleep duration for heart health. Actigraphy-based sleep irregularity has been identified as a stronger predictor of mortality than sleep duration. Whatever sleep-wake schedule is followed on one day must be maintained…