Weekend sleep shows failure to recover weekday sleep lost after early or later school start times

Among 35 pairs of students, mean sleep duration on weekends was practically identical regardless of weekday risetimes.

• Simulations suggested that weekend sleep duration does not increase to compensate for lost sleep on weekdays.
• Empirical data confirmed that students with different weekday wake-up times had similar weekend sleep durations.
• This phenomenon remained consistent across two subsets of students based on their weekday risetimes.
• The findings indicate a potential irrecoverable loss of sleep associated with earlier weekday wake-ups.

Simplified