Researchers Study The Effects of Sleeping Less Than 7-9 Hours a Day

sleep-study Brad Bennion

The reason our bodies need sleep has long been a mystery, but we know that skimping on sleep leaves us with foggy minds, irritable attitudes and a high risk of weight gain and other health complications.

Scientists have found that while we sleep, our bodies repair damaged cells and memories gained throughout the day are moved to long-term storage. They believe there may be multiple reasons why our bodies need sleep.

The National Sleep Foundation recommends that adults get seven to nine hours of sleep each night. Every person is biologically different, however, and some are only able to sleep for four hours a day, while others may doze for 12.

Psychology professor Dr. Paula Williams, radiology professor Dr. Jeffrey Anderson, and psychology graduate student Brian Curtis recently co-published a paper about the differences between “short sleepers” who consistently sleep less than six hours per day and “regular sleepers” who get the recommended amount of shut-eye.

Their research was inspired by a 2009 discovery in which the University of Utah’s Dr. Christopher Jones found a gene linked to short sleepers.

In this study, researchers first separated the short and regular sleepers from each other based off of their self-responses to a questionnaire. Each of those groups of sleepers was further broken down into people who said they felt tired or drowsy throughout the day and people who said they functioned fine on little sleep.

Eight hundred and thirty-nine participants, each falling into one of the resulting four groups, were asked to lie inside a functional magnetic resonance imaging (fMRI) scanner while researchers examined the connections between different sections of the subjects’ brains.

Researchers found that compared to people who slept for seven to nine hours a night, both groups of short sleepers yielded fMRI results which showed they were more tired and drowsy. This led the scientists to think that the short sleepers who reported functioning fine may only be doing fine when they are in exciting or otherwise stimulating environments.

“If true, this has public safety implications,” said Curtis. “Situations like driving a car at night without visual or auditory stimulation may put the short sleepers at risk of drowsiness or even falling asleep behind the wheel.”

However, the fMRI results also showed that short sleepers who reported no drowsiness through the day had more connections in the memory region of the brain than short sleepers who reported daytime dysfunction. The researchers see multiple possible explanations for this. It could be that this group of short sleepers are more efficient at storing memories in the brief amount of time they do sleep. Another possibility is that these people have been nodding off during the day, but not realizing it.

The team is still studying why some short sleepers may perform as well as regular sleepers. The next step in their research is to collect more data on short and regular sleepers, then compare the data. They will be looking at contrasts in sleep patterns, drowsiness, health and pain tolerance, among other aspects.

People who routinely sleep less than six hours a night and don’t perceive any ill effects can email Curtis ( to participate in the team’s ongoing research.