Much of modern sleep research has focused on the hormones, cells, and enzymes that regulate how we sleep, and what goes wrong when we can't sleep. But “all of this leaves unanswered the more fundamental question of why we need to sleep in the first place. What, in fact, is sleep’s function?” ask SFI's Van Savage and Geoffrey West in an essay for Aeon magazine.
“Until very recently we’ve lacked a quantitative theory that can predict, for example, why mice sleep roughly 10 times more per day than whales; why baby humans sleep roughly twice as long as adults . . ."
New scaling research is starting to fill the gap.
Read the essay, “Why do we sleep?” in Aeon (September 17, 2021)
Over the past few decades, huge amounts of data about the duration of sleep states have been gathered across species, as well as from birth to adulthood in humans. These findings have also been tallied with potential correlates such as melatonin, brain size, metabolic rate, lifespan, and sleep-promoting genes and neurons. Even so, until very recently we’ve lacked a quantitative theory that can predict, for example, why mice sleep roughly 10 times more per day than whales; why baby humans sleep roughly twice as long as adults; why REM and total sleep times change much faster as a baby grows in size than they do with similar size differences across species; and why temperature affects sleep times in cold-blooded animals such as fruit flies. Although great progress has been made in developing sophisticated models and explaining phenomena such as circadian rhythms, jetlag and details of EEG recordings of the sleeping brain, these advances are belied by the difficulty of developing a general quantitative theory for why we sleep.
Our work has started to fill this gap. Armed with a new, mathematical approach to the question of why we sleep, our framework leads to entirely new ways of understanding sleep data and responding to its basic questions...