Thursday, December 08, 2011

Sleep deprivation hurts memory and study habits


It’s that time of year; the library is packed as sleep deprived students strive to make sense of a semester’s worth of material for final examinations. According to Rebecca Spencer, professor of psychology, getting that good night’s sleep may be more important to a successful exam than all-nighters spent poring over textbooks.

Spencer, who is working on a series of studies testing the role of sleep across life spans, said sleep helps consolidate learning and processing new information.

Science of Sleep

Based on the results of her studies, she suggests that it is more beneficial to students learning to get more sleep rather than staying up all night to study.

Sleep is cyclical in nature. Of the stages, REM, or rapid eye movement sleep, helps with higher function thinking such as deciphering integrated questions and making connections between new information and old. Spencer said when studying for a cumulative final, for example, staying up all night to study isn’t helpful because one could miss out on that important sleep function.

“Without sleep we’re inattentive, we don’t have the focus it takes to even understand the questions,” she said.

However, Spencer suggested, staying up to cram for an exam tests the brain about new information recently learned, which is valuable so the information can enter your brain.

She compared the brain function during sleep to filing away messy papers neatly into a filing cabinet.

“During sleep, you take the movie of your day and replay the movie,” she said. When an event happens during the day, the brain stores that memory temporarily. While sleeping, the brain replays that memory, organizes and categorizes the memory until it is stored in a more permanent place, she said. Once the memory is processed during sleep and permanently stored away, it is easily accessible. Spencer also said sleep helps the brain prioritize thoughts and memories.

The brain is active during sleep, so the body uses a lot of energy to reactivate all of the information used during the day and organize it, said Spencer. Reprocessing information while sleeping is, “much more efficient, a good clean process that you can’t possibly do during the day.”

In addition to helping the brain to process information, sleep also helps it to organize emotionally-significant events, she said.

“Sleep allows you to process it and come to new emotional scenarios in a more calm way,” she said. “It packs away the past events and makes you less reactive, things aren’t hitting you in the context of other events while reprocessing it during sleep.”

The effects of not having enough sleep

Spencer said that a study published on the National Sleep Foundation’s website DrowsyDriving.org found that being awake for 18 hours causes impairment equivalent to having a Blood Alcohol Concentration of .05. After 24 hours of being awake, a person has the equivalent to a BAC of .10 which is over the legal limit of being drunk.

“It should be striking to these students,” said Spencer about the study.

She said severe sleep deprivation not only produces similar impairment to intoxication, but also accumulates and affects other tasks other than school. She noted that students who are sleep deprived, take their finals and then drive home immediately afterward, can be putting themselves in danger.

According to Robert Horowitz, a senior staff physician in family medicine at University Health Services, sleep deprivation can cause fatigue, problems with alertness and attention and higher order thinking such as making connections.

Sleep deprivation symptoms can be associated with anxiety, depression, low energy, low sex drive, poor judgment, decrease in immune function and respiratory viruses, said Horowitz.

To combat symptoms of sleep deprivation, Horowitz suggests that students take short 15 to 20 minute naps during the day to gain a few hours of alertness. But, if people take long take long naps during the day, it can affect their circadian rhythm – or biological clock – and throw off sleep patterns.

Sleep deprivation also affects mood and regulating emotions, said Spencer.

She said sleep deprived people have difficulty regulating emotions and tend to bounce between feeling giddy and grumpy. She said students going through a week’s worth of sleep deprivation can build up the emotional effects very quickly, and spiral out of control.

Horowitz said sleep deprivation symptoms can look like symptoms associated with ADD, mood disorders and can trigger latent psychological disorders like bipolar disorder.

To mitigate the fatigue during the day, exercise helps along with bright lights, short naps, and limited caffeine, said Horowitz. He said caffeine can be effective in moderate doses, but too much can result in shakiness, and palpitations.

“Energy drinks are really bad,” he said, “This time of year, people are up at night who have been drinking coffee come in [to UHS] shaky with rapid heartbeats, chest discomfort and a real sense of unwellness,” said Horowitz.

Student sleep pattern

Most people require eight hours of sleep, but seem people can get by with as little as four to six hours, said Horowitz.

Freshmen are especially affected by sleep deprivation because they aren’t totally accustomed to the college lifestyle. He said the average college student gets around 6.7 hours of sleep per night.

“This is something we frequently see. People come to school and they’re staying up later and later, taking naps during the day and never developing a normal sleep and wake cycle,” he said.

According to Spencer, the ideal night’s sleep would complete all of the sleep cycles. She suggested two 90-minute cycles of deep sleep, a 90-minute cycle of stage two sleep and then a 90-minute cycle of REM sleep totaling six hours.

Spencer said completing these stages of sleep is essential because of the different roles they play in the body. She said deep sleep, or slow wave sleep, helps with literal memory recall of information; stage two can help with motor skills; and REM sleep helps develop creativity, making connections and extrapolating information.

She also said consistency is important in sleep patterns. It may be harmful to sleep more on the weekends than during the week because you can build sleep pressure, she said.

Spencer frequently studies UMass students in her sleep research. She said based on her observations, the average college student gets six and a half hours of sleep per night. She said getting six to seven hours of sleep in per night is a reasonable goal for a college student and that it’s hard to detect because it varies across individuals. For example, Spencer said recently a gene was discovered for “short sleepers,” or people who only need about five hours of sleep a night.

Spencer warned taking an exam at a different time of day than the regular class time may be aversive to the test taker because they are forced to recall the information at a time they’re not normally used to. She suggested getting extra sleep in the night before.

Spencer said two things drive sleep: the circadian clock and sleep pressure. Circadian clock, or rhythm, refers to the biological clock that runs on a 24-hour cycle. Sleep pressure, Spencer said, is like a thermostat. The less you sleep, the more sleep pressure you build up until it gets to the point where no matter where you are in your circadian rhythm, your body will force you to sleep.

“It’s not the quantity of sleep, it’s the quality,” said Spencer about how many hours of sleep people need per night.

Louie Pires, a junior chemistry major, said he gets at least six to eight hours of sleep per night. He said when he doesn’t get enough sleep, he feels drowsy and “not all there.”

Senior anthropology major Zahir Delrosario gets slightly more time each night, sleeping an average of eight to nine hours, but wished he could sleep 10 to 12 hours. He said after the weekend he feels “bummed out” that he has to wake up early for classes.

Read more: http://dailycollegian.com/2011/12/08/sleep-deprivation-hurts-memory-and-study-habits/

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