The 2-Process Model of Sleep Regulation

In 1982, Dr. Alexander Borbely published an article in the journal Human Neurobiology describing something he called the 2-process model of sleep regulation. This conceptual framework for sleep describes two processes that occur simultaneously to regulate sleep and wake states.

Process 1 is sleep pressure. Basically, sleep pressure mounts from the moment you wake up, to the time when you go to sleep. While you're sleeping, pressure decreases. If you get a full night of sleep, you start the next day with low sleep pressure.

Process 2 is wake drive, which counteracts sleep pressure and is controlled by a 24-hour rhythm that repeats in a wave-pattern.

It's important to understand this process because it helps reveal an important point about sleep in our modern world that I learned from sleep scientist Dan Pardi:

For millions of years, humans and our ancestors have evolved to sleep at night (when it is dark) and wake during the day (when it is light). However, in the modern world, we work inside all day, often in areas that are darker than the outside world. And then, at night, we look at bright screens and televisions. Low light during the day, more light at night: It's the opposite of naturally occurring cycles and it seems quite likely that it could mess up your wake rhythm and circadian rhythm.

The result of this shift? Drowsiness and impaired function through the day. We'll talk more in just a minute about how to sleep better, including actionable steps you can take to anchor your rhythm, but it pretty much comes down to this: Use common-sense light habits. Get outdoor light exposure during the day, and turn down the lights and turn off your screens after dark.