New Study Says Bedtime Routines are Part of Our Survival Instinct

Kyoko Tossell, Ph.D., one of the study’s lead researchers, told Sleep Foundation that the inclination to prepare for sleep is likely a “hard-wired process in the brain.” But, we “often neglect [maintaining a bedtime routine] as we grow older.” 

To understand how mammals prepare for sleep, the research team looked at the brains and actions of mice. First, they made the mice feel sleepier by showing them unusual items, like Legos and other toys, to keep them awake for five hours beyond their regular bedtimes. 

As the mice became sleepier, the researchers watched how they acted and what happened in their brains. The study team used methods called optogenetics and chemogenetics to watch the mice’s brain activity. 

Mice took more actions to prepare for sleep as they became more tired. Tossell shared that these preparation activities included seeking a safe location and building a comfortable and hygienic nest near the water and food supply. 

As the mice prepared for sleep, nerve cells in the front of their brains (the prefrontal cortex) sent messages to the base of the brain (the hypothalamus), which controls many actions related to survival, like sleeping and eating.

“When tiredness starts to wash over the mouse, the top part of the brain decides to implement behavior to make sure the mouse is in a safe and comfortable place before going to sleep,” Tossell says.

Tossell explained in a university news release that “It is very likely that the same wiring exists in the human brain as the mouse brain [and] we are probably governed by unconscious urges to prepare for bed as mice are.”

William Wisden, Ph.D., Chair of Molecular Neuroscience at Imperial College London and another researcher on the study, told the university’s news team that preparing for sleep is “a survival feature.” Wisden also suggests that many humans likely ignore this natural tendency. 

Both Tossell and Wisden encourage people to take good sleep hygiene seriously. Examples Wisden gave include going to bed at a set time, avoiding digital devices before bedtime, and sleeping on a good mattress with nice sheets and blankets.

More research is needed to determine exactly how this tendency to prepare for sleep affects humans, but following regular bedtime routines and optimizing our bedroom environments so we feel safe and comfortable can help us get quality rest.