Secondly, sleeping in after a bad nightís sleep or on the weekend reduces what sleep researchers call prior wakefulness. Prior wakefulness refers to the amount of time that has elapsed from the time you rise in the morning until you turn off the lights at bedtime. Our sleep system follows a basic principle: the greater the amount of prior wakefulness, the greater the brainís pressure for sleep and the better we sleep.
What is sleep pressure?
Sleep researchers believe that sleep pressure is the result of a sleep-inducing neurotransmitter in the brain called adenosine accumulating with each hour of prior wakefulness. With increasing prior wakefulness, we also increase sleep pressure due to increased cerebral and physical energy expenditure during the day. See Sleep Basics for more information on the physiology of sleep. Since sleeping in reduces prior wakefulness, it reduces sleep pressure and makes it harder to sleep.
Sleep scheduling guideline #1: Get out of bed within a half hour of the same time every day, including weekends, no matter how little or poorly you have slept. The more consistent your wake time, the more consistent your body temperature rhythm and prior wakefulness and the more consistent your sleep.
Another common strategy to cope with insomnia is to spend more and more time in bed in an effort to catch up on lost sleep. This may involve going to bed earlier or staying in bed later, or both. However, spending more time in bed actually increases sleep problems for several reasons. First, increased time in bed reduces prior wakefulness, which disturbs sleep. Secondly, increased time in bed leads to lower sleep efficiency, which makes the bed a stronger cue for wakefulness.