You don’t have to be awake for your brain to continue processing information, according to Michigan State University researchers in East Lansing. And, in fact, the brain may process memory activities better during sleep than when someone is awake.

In a recent study of 255 people, participants divided into two groups were given sets of 40 paired words to memorize. Examples include “animal” and “fox,” and “journey” and “map.” All pairs contained words already associated with each other. One group was given the terms at 9 a.m. in the morning before a waking interval, and the other at 9 p.m. before a sleep interval.

The participants were tested once immediately after seeing the paired associates to get an initial measurement of their learning (how many pairs they could recall), and once 12 hours later. The group that went home and slept recalled an average of four more pairs than they did on the initial test, whereas the group that was tested after a waking interval on average recalled only one more pair.

“The ability to process memory during sleep is probably affecting the way you process memory during your waking day,” said Kimberly Fenn, a psychology professor at Michigan State and lead researcher of the study.

This unconscious “sleep memory” can also help improve your long-term memory, which helps when you want to remember something when you’re awake, according to Fenn.

“Even taking a nap can help your memory,” she said.

Anna Fedick, a 20-year-old student at Boston University, said she gets on average at least eight hours of sleep each night in addition to taking a one or two-hour nap most days.

“I wait to do my homework until after I take a nap because then my brain resuscitates and it sets me up to be a lot more focused,” said Fedick. “When I’m not getting enough sleep I forget things – I lose things, leave things places.”

Two significant problems happen when people don’t get sufficient sleep, according to Fenn. First, you probably won’t get as much benefit when you actually do get rest. Second, when you learn in a sleep-deprived state, research shows that your brain is not as well equipped to process the new information.

“We’ve known for a long time that sleep is important for health and cognition, but the general public isn’t taking this information seriously,” said Fenn. “People don’t realize how much they learn in a given day – the face of a new friend or a new name. Getting more sleep could help you with your everyday social interactions.” 

The exact amount of sleep a person needs varies depending on the individual.

Pooja Panigrahi, 21, is a graduate engineering student at Northwestern University who gets four to five hours of shut-eye.

“I perform better with less sleep to be honest,” said Panigrahi. “ I guess it’s less time between sessions of intense studying.”

“I feel the difference when I’ve gotten less sleep when I’m just waking up. But, within 30 minutes, I’d say I’m at the same level of functioning as when I get more sleep.”

Still, many doctors and sleep researchers recommend between seven and nine hours of sleep each night for optimum cognitive productivity.

“Adequate nightly sleep duration and quality are critical for optimal mental, physical and emotional health,” said James K. Wyatt, director of the Sleep Disorders Service and Research Center at Rush University Medical Center. “It’s really that simple.”