New Research on Sleep and Memory

Sleep plays a critical role in how we learn and how we remember. Learn about the latest studies involving the brain, memory, and how much sleep you need.

It is well-known that a good night’s sleep is critical for a healthy body. Now recent research has shown that sleep is even more important when it comes to learning and memory than previously thought.

“If you shorten sleep both short-term (one night) or long-term (more than two weeks), the ability to retain newly learned information decreases,” says Robert Oexman, DC, director of the Sleep to Live Institute in Joplin, Mo. “This would be new information, as well as new tasks like playing a piano or guitar.”

Making Memories

Creating a memory requires three functions: acquisition of the memory; consolidation, in which the memory becomes stable in the brain; and recall, in which you are able to access the information later. And while acquisition and recall always happen while you’re awake, experts theorize that consolidation takes place during sleep.

Though the process of memory creation is still largely unknown, researchers think that the type of brainwaves produced during different kinds of sleep play a role in the creation of stable memories. For example, one study found that students involved in an intensive language course had more rapid-eye movement (REM) sleep. The researchers believe that this may represent the body’s attempt to consolidate all of that learning by increasing REM sleep, which may be when this memory consolidation occurs.

“Processes that occur during sleep help consolidate and store information that can later be retrieved,” says Raman Malhotra, MD, co-director of the Saint Louis University Sleep Disorders Center. “When humans get poor sleep or suffer from sleep disruption, they perform worse on memory testing and neuropsychological testing.”

The phenomenon has been researched numerous times, but one of the most interesting studies recently took place in Belgium. Researchers had subjects study several photos. Then half the subjects were allowed to get a decent night’s sleep, while the others were sleep-deprived. Six months later, the brains of the participants were monitored as they studied the same group of pictures. The results were clear: The group that had slept the night after first studying the pictures had much greater memory and recognition than the group that had not slept.

Why the Brain Needs Sleep

Research has shown emphatically that the brain needs sleep to learn and remember things. But exactly why sleep is necessary for this process isn’t clearly known. “To date, this is poorly understood,” says Dr. Oexman. “Theories exist that range from purging useless information to strengthening the neuronal process for certain information to be recalled.”

What is clear is that almost all aspects of learning — from studying for a big test to practicing driving a car — require sleep to help the brain retain and remember what is useful. “Most skills are tied to sleep,” says Oexman. “Athletic skills seem to improve with sleep. Motor skills, such as playing a piano, improve with sleep. Math and word recall are enhanced after a good night of sleep.”

Dr. Malhotra adds that some skills might be more affected by sleep than others. “Almost all brain function is affected by sleep loss, but there are certain aspects that are more sensitive,” he says. “Reflexes, fine motor skill, memory, attention, and decision-making are all sensitive to sleep loss.”

How Much Sleep Do You Need?

If you have children, then you know that they can often be champions of sleep. While we settle for our precious six to eight hours every night, they will often go for 10 hours or more, as well as a nap or two during the day.

Part of the reason for all this sleep is because children are growing so much physically, and much of the growth hormone needed for that process is secreted during sleep. But the other reason is that their brains are processing and learning so much new information. “It is possible that one reason babies and children need more sleep than adults is that they are needing to process and store more information than adults,” says Malhotra. “It is also likely that sleep plays a role in letting the brain develop and mature during childhood.”

As for your sleep needs, a healthy adult should strive for the eight-hour range every night to preserve healthy learning and memory function. “Most sleep disorder specialists would recommend 7.5 to eight hours of regular, nightly sleep to allow for peak functioning,” says Philip Alapat, MD, medical director of the Baylor College of Medicine Sleep Center in Houston, “though individuals differ, with some requiring less and some requiring more.”

By Wyatt Myers – Medically reviewed by Lindsey Marcellin, MD, MPH