Sleep your way to better memory

Copyright (c) 2008 Mary Ann Copson

Here is a timely question for final exam season from one of my clients who is a law professor:

"I am teaching my law students a class on preparing to take exams. I have all the usual exam preparation information but is there any new slant on things you can offer to facilitate their performance?"

The best advice you can offer your students is for them to “sleep on it.” Research shows that getting a good night’s sleep facilitates memory consolidation. Sleep appears to help the brain commit new information to memory. Without a good night’s sleep your students mental processing time will slow down and they are more likely to make poor decisions plus their thinking will be foggy and they will have poorer concentration. If your students don’t get enough sleep their memory will be impaired and their ability to think and process information will be impaired.

Throughout the day there is an important sleep chemical called adenosine that builds up in the brain. The more you use the brain (e.g. study) the more adenosine builds up. As adenosine builds up it slows down the rate of nerve firing in the brain and you get sleepy. Adenosine also increases blood flow to the brain, which helps the brain restore itself more efficiently during the night. While you sleep, your brain recycles adenosine to use the next day. If you don’t sleep long enough to reprocess your brain’s supply of adenosine you will stay sleepy until you do sleep long enough to clear the residual adenosine. The more your students are using their brain the day before the exam (i.e. by studying) the more sleep they may need the night before the exam to avoid that sleepy state created by unprocessed adenosine.

Also, the quality of their sleep is important for improving their cognitive functioning. Good quality sleep is composed of five distinct stages during which the brain’s activity changes.

In stage I, you drift toward sleep and the brain’s electrical activity slows. Stage II is a light sleep in which your body prepares for deep sleep by lowering body temperature and relaxing muscles. In stages III and IV you enter slow wave sleep. REM (intense dreaming) sleep occurs in Stage V.

Your body is restored during slow wave sleep in stages III and IV. In Stage V – REM sleep- your mind is restored. It is during Stage V sleep that the neural connections are made that support the retention and organization of information and space is created to learn new information and tasks. All of these five stages together compose one sleep cycle.

Each sleep cycle lasts 90-120 minutes. For improved cognitive performance it is important that you cycle through these five stages of sleep for a full five to six cycles a night. If you are not going through the full five stages of sleep and descending down into REM sleep your ability to retain information, organize your memories, and prepare to learn something new will be compromised. Also, the longer you are in REM sleep the more aggressively your brain will recycle adenosine and the more refreshed you will feel when you wake up.

Some research even suggests that if you are an early riser and miss that late stage of sleep that your performance on learning certain tasks may decrease by 20%. It appears that during sleep your brain organizes all information you learned that day, sends some information to long term storage, other information gets deleted, and some is slated for retention and redesignation in the next sleep cycle. The brain uses a good night’s sleep to consolidate memories and skills learned during the day.

If your students will be taking their exam later in the day you can advise them to become good nappers. Research shows that frustration and poorer performance on mental tasks sets in as the day goes on. Scores on some mental tasks appear to worsen over the course of a day. But taking a 30 minute nap prevents this deterioration and a one hour nap actually boosts later day performance to morning levels. If your students can nap long enough (50-60 minutes) and thus cycle through their slow wave deep sleep their learning may be fostered. Even a 20 minute power nap can be helpful.

The average need for good quality sleep is between 7 and 8 hours a night with some of us needing up to 10 hours and a few needing 6 hours. So helping your students learn and find ways to get the amount of sleep they need can go a long way in helping them to perform better with less struggle. Hope that helps!