Sleep timing, sleep consistency, and health in adults: a systematic review

This systematic review explored how sleep timing (e.g., bedtime and wake-up time) and consistency (e.g., variability in sleep duration, social jetlag, weekend catch-up sleep) affect health outcomes in adults. Analyzing 41 studies with over 92,000 participants, the review found that later sleep timing and inconsistent sleep schedules are generally linked to poorer health, including mental health and cognitive decline. Regular sleep patterns with consistent bedtimes and wake times are associated with better health outcomes. This highlights the importance of regular sleep schedules for maintaining brain health and cognitive performance.

To improve brain health and cognitive function, aim for consistent bedtimes and wake times, avoiding significant variability. While evidence suggests benefits, findings are mixed, and further research is needed to define precise thresholds. Adjustments should align with individual schedules and lifestyle.