Weekday and weekend sleep times across the human lifespan: a model-based simulation

Area of Science:

• Sleep science
• Chronobiology
• Neuroscience

Background:

• Sleep timing shifts toward later and earlier during adolescence and adulthood, respectively.
• Sleep duration shows an inverse relationship with age, unlike sleep timing.
• Variations in circadian and homeostatic sleep regulation mechanisms likely cause these age-associated differences.

Purpose of the Study:

• To find a parsimonious explanation for differing age-related sleep timing and duration patterns.
• To simulate sleep patterns using a two-process model of sleep regulation.

Main Methods:

• Utilized 1404 samples of reported weekday and weekend sleep times, divided into 15 age subsets.
• Performed simulations of sleep times, considering age-associated variations in circadian phase.

Main Results:

• Age-associated decay of slow-wave activity explains decreased weekend sleep duration.
• This decay also accounts for the reduced rate of sleep pressure buildup during wakefulness.
• The model successfully explains both the delay in sleep timing during adolescence and the advance during adulthood.

Conclusions:

• Functional relationships exist between age-related changes in sleep duration, sleep pressure, and slow-wave activity.
• Slow-wave activity serves as an electrophysiological marker for cortical metabolic rate and synaptic plasticity.
• These findings offer a unified explanation for age-dependent sleep regulation dynamics.