The two hormones involved in the sleep and wake cycle have a role as well: Melatonin and cortisol levels differ significantly between the two groups of people over the course of a 24-hour period. A study published in January in Nature Communications found that genes can even shift a person’s natural waking time by up to 25 minutes. Why some people are primed to wake up early and others are driven to go to bed late stems from their genes. Facer-Childs explains that this likely means their brains were more primed for doing tasks and being less sleepy. Ultimately, they found that “morning larks” had higher resting brain connectivity - which in turn was associated with better attentional performance and lower daytime sleepiness over the course of the working day. "Night owls" are less compatible with the 9-to-5 work week. They were also asked to report on their levels of sleepiness and when during the day they felt most alert.
Lead author and University of Birmingham researcher Elise Facer-Childs, Ph.D., explains to Inverse that while varying levels of brain connectivity do not always relate to something negative, in this study, lower levels were less than positive.ĭuring the experiment, the scientists evaluated the brain function of 38 people while they slept, measuring their levels of melatonin and cortisol with MRI scans. Scientists shared their findings Friday in the journal SLEEP, with the article, “Circadian phenotype impacts the brain’s resting state functional connectivity, attentional performance and sleepiness.” In a new study, scientists report that people whose internal body clocks tell them to go to bed late, but are then forced to wake up early, have a lower resting brain connectivity in the regions of the brain linked to consciousness. But however normalized the schedule, it is directly opposed to something more powerful: biology. The 9-to-5 workday originated with American labor unions in the 1800s, and today, the eight-hour workday is the norm.