The Secret Life of Sleep (2014) takes an enlightening look at what exactly sleep is. Using cutting-edge scientific research and examples from cultures around the world, Kat Duff explores why and how we sleep, and what makes some Western sleeping patterns particularly unhealthy.
We’re all familiar with that murky yet calm feeling we get as we slip into dreamland, but how do we actually fall asleep? Some say the Sandman comes and sprinkles sand into your eyes, the Blackfoot Indians believe a butterfly visits to help you drift off and the ancient Greeks believed in Hypnos, the god of sleep. But what can science tell us about sleeping?
Well, a sleep switch in humans has been discovered.
In 2001, Harvard University sleep researcher Clifford B. Saper identified a group of neurons in the hypothalamus – the brain region that controls metabolic processes and activities such as hunger and body temperature – called the sleep switch.
Our bodies have a mechanism to chemically regulate sleep. It functions independently of day and night and maintains internal balance by making you sleep more or less, thanks to a chemical called adenosine triphosphate (ATP). ATP depletes over the course of the day, making us increasingly tired until we fall asleep. Then, during our sleep, other chemicals gradually accumulate until they reach a tipping point, causing us to wake up.
The state when these neurons are shutting down and we begin to fall asleep is known as hypnagogia, and its parallel transitional state when we wake up is called hypnopompia.
During these transitional states, we often gain insight or feel inspired. We may also relive daytime events, see geometric patterns in our vision, feel like we’re falling or floating, or think we’re expanding and contracting in size.
As French philosopher Jean-Luc Nancy put it, it’s at these times that we “coincide with the world” and have a chance to access other dimensions or realities. Salvador Dalí famously made use of this in his paintings, which were inspired by his dreams.
Thomas Edison also used these transitional states to solve problems by taking naps while holding steel balls in his hands. As he drifted off, his hands would relax and the balls would fall and wake him up, hopefully with a solution already in mind!