A good night’s rest helps the brain consolidate memories. Students, take note.
Getting shut-eye before tests boosted performance, study found
(HealthDay News) — Besides helping you feel well-rested, getting your zzz’s may also sharpen your memory, a new study shows.
Researchers found that sleep not only protects memories from outside interferences, it also helps strengthen them.
"There was a very large benefit of sleep for memory consolidation, even larger than we were anticipating," said study author Dr. Jeffrey Ellenbogen, an associate neurologist at Brigham and Women’s Hospital, Boston, and a postdoctoral fellow in sleep medicine at Harvard Medical School.
In the study, the researchers focused on sleep’s impact on "declarative" memories, which are related to specific facts, episodes and events.
"We sought to explore whether sleep has any impact on memory consolidation, specifically the type of memory for facts and events and time," Ellenbogen said. "We know that sleep helps boost memory for procedural tests, such as learning a new piano sequence, but we’re not sure, even though it’s been debated for 100 years, whether sleep impacts declarative memory."
The study involved 48 people between the ages of 18 and 30. These participants had normal, healthy sleep routines and were not taking any medications. They were all taught 20 pairs of words and asked to recall them 12 hours later. However, the participants were divided evenly into four groups with different circumstances for testing: sleep before testing, wake before testing, sleep before testing with interference, or wake before testing with interference.
Two of the groups (the wake groups) were taught the words at 9 a.m. and then tested on the pairings at 9 p.m., after being awake all day. The other two groups (the sleep groups) learned the words at 9 p.m., went to sleep, and were then tested at 9 a.m.
Also, prior to testing, one of the sleep groups and one of the wake groups were given a second list of 20 word pairs to remember. These groups were then tested on both lists to help determine memory recall with interference (competing information).
The result: Sleep appeared to help particpants recall their learned declarative memories, even when they were given competing information.
According to the researchers, people who slept after learning the information performed best, successfully recalling more words whether or not there was interference. Those in the sleep group without interference were able to recall 12 percent more word pairings from the first list than the wake group without interference (94 percent recall for the sleep group vs. 82 percent for the wake group).
When presented with interference, those who slept before testing did significantly better at remembering the words (76 percent for the sleep group vs. 32 percent for the wake group).
"We were surprised to find the order of magnitude by which the data demonstrated our effects," Ellenbogen said.
Jan Born, a professor of neuroendocrinology at the University of Lübeck in Germany, said the study offers more proof of the importance of sleep for memory consolidation.
"Considering that learning in every educational setting (schools, colleges, etc.), is centrally based on hippocampus-dependent memory function [declarative memories], people should realize that optimal learning conditions require proper sleep," he said.
Proper sleep may have other benefits, too, added Michael Perlis, director of the Sleep Research Laboratory at the University of Rochester in Rochester, NY. Research has shown that in addition to memory, sleep may be related to physical functioning, good immune function, physical and cognitive performance, and mood regulation, he said.
"These are all theories. The only thing we know is that when we’re deprived of sleep, we do less well. Is that a lack of sleep or sustained wakefulness? It’s very difficult to figure out how to crack that nut," he said. "We spend 30 percent of our time on sleep. What is sleep for? This is a riddle we’re still working on."
For more on the importance of sleep, visit the National Sleep Foundation.
You Are Getting Sleepy
How to fight the need to sleep and sleep.
Wouldn’t it be nice to curl up and take a nap right now? About twenty million insomniacs pace the halls each night, but it’s difficult to assess how many people suffer from excessive daytime sleepiness, known as hypersomnia. The National Sleep Foundation estimates that up to 40 percent of Americans have at least some of the condition’s symptoms some of the time. Its consequences are worse than decreased productivity: Fatigue causes at least 100,000 car accidents per year, estimates the U.S. National Highway Traffic Safety Administration.
Mass drowsiness can’t be pinned on any one culprit. "Sleep lives at the nexus of our social life, biology, and behavior," says James Wyatt, director of the Sleep Disorders Service and Research Center at Rush University Medical Center in Chicago. Wyatt and his colleagues send patients an eight-page questionnaire and meet with them for an hour before arriving at even a preliminary diagnosis. "We’re not looking for the smoking gun, we’re looking for all the indicators… it could be a biological sleep disorder, it could be a medication you are taking, and it could also be that you live near an airport or sleep with a noisy pet."
In a Trance
Hypersomnia is not merely feeling tired after a late night out. It’s a stronger, more consistent sleepiness that compels you to nap, even at inappropriate times. See your primary care physician if you have a particularly hard time waking up, if you are especially anxious and irritable, and/or if you’ve lost your appetite. Unsurprisingly, excessive daytime sleepiness can cloud your thinking and mar your memory or even spur hallucinations.
You can make yourself sleepy by repeatedly staying up. But narcolepsy, a neurological condition marked by uncontrollable urges to sleep, or sleep apnea, which causes interrupted breathing during sleep, are involuntary potential root causes. Factors that bring on hypersomnia (separately or in combination) also include depression or bipolar disorder, the use of prescription medicines, drug or alcohol abuse, a head injury, and a genetic predisposition toward drowsiness.
Hypersomnia can indeed be treated. Once a doctor determines what is causing your sleepiness, he or she would treat a primary sleep disorder first. Sufferers of sleep apnea, for example, may be advised to use a CPAP (continuous positive airway pressure) device, a mask attached to a machine that blows air to keep nasal passages open during the night. Antidepressants could be prescribed if your doctor believes depression, anxiety, or bipolar disorder is causing your excessive sleepiness. Stimulants are also a common treatment for hypersomnia—and new drugs such as modafinal are thought not to be habit-forming. Exposure to artificial bright light in the morning can help reset your body’s internal clock. Your doctor may advise you to cut down on your drug, alcohol and caffeine, or may use cognitive-behavioral therapy techniques to help you establish a more consistent sleep routine.
You’ve heard some of these sleep hygiene tips before, no doubt, but incorporating them requires not just knowledge but self-discipline. Try keeping a sleep diary each day to hold yourself accountable as you develop better habits. Most importantly, go to bed and wake up at set times. Try to exercise for at least 20 minutes, preferably five to six hours before bedtime. Establish a relaxing nighttime ritual such as taking a warm bath or reading—avoid watching TV or surfing the Internet too late as those images will get your mind racing when it should be settling down.
This topic discusses simple snoring. If you stop breathing, choke, or gasp during sleep, you may have a potentially serious condition called sleep apnea. For more information, see the topic Sleep Apnea.
What is snoring?
Snoring occurs when the flow of air from the mouth or nose to the lungs is disturbed during sleep, usually by a blockage or narrowing in the nose, mouth, or throat (airway). This causes the tissues of the airway to vibrate and knock against the back of the throat, resulting in a noise that can be soft, loud, raspy, harsh, hoarse, or fluttering.
You may not know that you snore. Your bed partner may notice the snoring and that you sleep with your mouth open. If snoring interferes with your or your bed partner’s sleep, either or both of you may feel tired during the day.
In the past, snoring was often considered no more than a nuisance that kept a bed partner awake at night. However, snoring may progress to upper respiratory resistance syndrome and obstructive sleep apnea, a potentially serious sleep disorder in which you periodically stop breathing during sleep. Because of this, it is important to see your health professional if you routinely snore.
Snoring is common. About 25% to 50% of men and about 25% to 30% of women snore on a regular basis.1
What causes snoring?
You snore when the flow of air from your mouth or nose to your lungs makes the tissues of the airway vibrate. This usually is caused by a blockage (obstruction) or narrowing in the nose, mouth, or throat (airway).
When you inhale during sleep, air enters the mouth or nose and passes across the soft palate (the back of the roof of the mouth) on its way to the lungs. The back of the mouth—where the tongue and upper throat meet the soft palate and uvula—is collapsible. If this area collapses enough, the airway becomes narrow or blocked. The narrowed or blocked passage disturbs the airflow, which causes the soft palate and uvula to vibrate and knock against the back of the throat, causing snoring. The tonsils and adenoids may also vibrate. The narrower the airway is, the more the tissue vibrates, and the louder the snoring is.
How is it treated?
You may be able to treat snoring through lifestyle modifications such as losing weight (if necessary), quitting smoking, changing sleep habits (such as sleeping on your side instead of your back), and avoiding the use of alcohol and sedatives before bed. If nasal congestion is disturbing airflow, nasal dilators (such as nasal strips), decongestants, or nasal corticosteroid sprays may be used. Oral breathing devices, which push the tongue and jaw forward to improve airflow, may also be an option. If these treatments do not work, continuous positive airway pressure (CPAP) or surgery may be tried.
Snoring is not always considered a medical problem, so insurance may not cover treatment.
Frequently asked questions
Learning about snoring:
Living with snoring: