Sleep Now, Remember Later
Researchers are exploring the mysterious and important links between memory and slumber.
Published Apr 18, 2009
From the magazine issue dated Apr 27, 2009
For many years, people believed that the brain, like the body, rested during sleep. After all, we are rendered unconscious
by sleep. Perhaps, it was thought, the brain just needs to stop thinking for a few hours
every day. Wrong. During sleep, our brain - the organ that directs us to sleep - is itself
extraordinarily active. And much of that activity helps the brain to learn, to remember and to make connections.
It wasn't so long ago that the rueful joke in research circles was that everyone knew
sleep had something to do with memory - except for the people who study sleep and the people who study memory. Then, in 1994, Israeli researchers reported that the average performance
for a group of people on a memory test improved when the test was repeated after a break of many hours - during which some
subjects slept and others did not. In 2000, a Harvard team demonstrated that this improvement occurred only during sleep.
There are several different types of memory - including:
- declarative (retrievable, fact-based information)
- episodic (events from your life)
- procedural (how to do something)
and researchers have designed ways to test each of them.
In almost every case, whether the test involves remembering pairs of words, tapping numbered
keys in a certain order or figuring out the rules in a weather-prediction game, "sleeping
on it" after first learning the task improves performance. It's as if our brains squeeze in some extra practice time while
This isn't to say that we can't form memories when we're awake. If someone tells you
his name, you don't need to fall asleep to remember it. But sleep
will make it more likely that you do. Sleep-deprivation experiments have shown that a tired brain has a difficult time capturing
memories of all sorts.
Interestingly, sleep deprivation is more likely to
cause us to forget information associated with positive emotion than information linked to negative emotion. This could explain,
at least in part, why sleep deprivation can trigger depression in some people:
memories tainted with negative emotions are more likely than positive ones to "stick"
in the sleep-deprived brain.
Sleep also seems to be the time when the brain's two memory systems - the hippocampus
and the neocortex - "talk" with one other. Experiences that become memories are laid down first in the hippocampus, obliterating
whatever is underneath.
If a memory is to be retained, it must be shipped from the hippocampus to a place where
it will endure - the neocortex, the wrinkled outer layer of the brain where higher thinking takes place. Unlike the hippocampus,
the neocortex is a master at weaving the old with the new. And partly because it keeps incoming information at bay, sleep is the best time for the "undistracted" hippocampus to shuttle memories to the neocortex,
and for the neocortex to link them to related memories.
How sleep helps us consolidate memories is still largely
a mystery. A recent study from the University of Lübeck, in Germany, offers one clue. Subjects were given a list of 46 word pairs to memorize, just before sleep.
Shortly after they fell asleep, as they reached the deepest stages of sleep, electrical
currents were sent through electrodes on their heads to induce very slow brain waves.
Such slow waves were induced at random in the brains of one group of subjects, but not
another. The next morning, the slow-wave group had better recall of the words. Other types of memory were not improved, and
inducing the slow waves later in the night did not have the same effect. Why and how the slow waves improved memory is not
yet understood, but they are thought to alter the strengths of chemical connections, or synapses, between specific pairs of
nerve cells in the brain. Memories are "stored" in these synapses: changing the strength of the synapses increases the strength
of the memories they store.
It's not just memory that is improved by sleep. Recent
studies indicate that sleep not only helps store facts, it also helps make connections between
them. Scientific history is replete with tales of scientists with nocturnal "aha!" experiences. Dmitri Mendeleev awakened
from a dream that gave him the idea for the periodic table of elements - a landmark in chemistry. Such anecdotes don't prove
that sleep can produce insights, but a recent study by Ullrich Wagner and colleagues in Germany does. Wagner used a puzzle in which players were given a string of numbers, and required to make
a series of seven calculations based on these numbers.
The seventh calculation (which depended on the preceding
six) was the "answer." Participants repeatedly played the same game with the same rules, but different sets
of numbers. Some of the players played the game in the morning, then did other things for eight hours or so, then played the
game again. Others played the game first in the evening, then slept, then played it again after awakening.
The players who slept did somewhat better - but that was not the important result. Cleverly,
the researchers structured the game such that the second calculation always gave the same answer as the seventh calculation
- the final answer. If players recognized this "hidden rule," they could get to the final answer much faster - and speed was
a part of the game. The players who slept were almost three times more likely to have the insight that allowed them to spot
the hidden rule - even though none of the players had been told there was a hidden rule to spot. Sleeping
had allowed them to connect the dots.
Why is this important? Some sleep researchers believe that for every two hours we spend awake, the brain needs an hour of sleep to figure out
what all these experiences mean, and that sleep plays a crucial role in constructing the
meaning our lives come to hold. Breakdowns in such sleep-dependent processing may contribute
to the development of depression, and may explain why some people who experience horrific traumas go on to develop PTSD.
A better understanding of how sleep knits our memories
together could lead to new technologies that improve learning, memory and creativity, and even help treat some psychiatric
disease. But perhaps the most important reason for studying sleep is simply this:
we are a curious species; we spend about a third of our lives asleep; and we realize how
little we understand about that third of our lives. So we continue experimenting, hoping to understand sleep better. And perhaps someday we will. After we've slept on it.
Stickgold is associate professor of psychiatry at Harvard Medical School and Beth Israel Deaconess Medical Center.
Wehrwein is editor of the Harvard Health Letter. For more information, go to health.harvard.edu/Newsweek
source site: Newsweek Online
MSNBC/MSN Online Health
Suggestions for Better Sleep
The following suggestions can help you achieve better sleep
and the benefits it provides. If you have trouble falling asleep, maintaining sleep, awaken
earlier than you wish, feel tired after sleep, you may want to consult your physician. Be
sure to tell him/her if you have already tried these ideas and for how long.
a regular bed and wake time schedule including weekends. Our sleep-wake cycle is regulated
by a "circadian clock" in our brain and the body's need to balance both sleep time and wake
time. A regular waking time in the morning strengthens the circadian function and can help with sleep
onset at night. That is also why it is important to keep a regular bedtime and wake-time, even on the weekends when there
is the temptation to sleep-in.
Establish a regular, relaxing bedtime routine such as soaking in a hot bath or hot tub and then reading a book or listening to soothing music. A relaxing, routine activity right before bedtime conducted away from bright lights helps separate your sleep
time from activities that can cause excitement, stress or anxiety which can make it more difficult to fall asleep, get sound
and deep sleep or remain asleep.
Avoid arousing activities before bedtime like working, paying bills, engaging in competitive games
or family problem-solving. Some studies suggest that soaking in hot water before retiring to bed can ease the transition into
deeper sleep, but it should be done early enough that you are no longer sweating or over-heated.
If you are unable to avoid tension and stress, it may be helpful to learn relaxation therapy from a trained professional. Finally, avoid exposure to bright light before bedtime because it signals the neurons that help
control the sleep-wake cycle that it is time to awaken, not to sleep.
Create a sleep-conducive environment that is dark, quiet, comfortable
and cool. If your mattress is not comfortable and supportive, you might consider investing in an upgrade. Have comfortable
pillows and make the room attractive and inviting for sleep but also free of allergens that
might affect you and objects that might cause you to slip or fall if you have to get up during the night.
Design your sleep environment to establish the conditions you
need for sleep – cool, quiet, dark, comfortable and free of interruptions. Consider
using blackout curtains, eye shades, ear plugs, white noise machines, humidifiers, fans and other white noise devices to block
Finish eating at least 2-3 hours before your regular bedtime. Eating
or drinking too much may make you less comfortable when settling down for bed. It is best to avoid a heavy meal too close
Also, spicy foods may cause heartburn, which leads to difficulty falling asleep and discomfort during the night. Try to restrict fluids close to bedtime to prevent
nighttime awakenings to go to the bathroom, though some people find milk or herbal, non-caffeinated teas to be soothing and
a helpful part of a bedtime routine.
Exercise regularly. It is best to complete your workout at least a few hours before bedtime. In general, exercising regularly makes it easier to fall asleep and contributes to sounder sleep. However, exercising
sporadically or right before going to bed will make falling asleep more difficult.
In addition to making us more alert, our body temperature rises during exercise, and takes as
much as 6 hours to begin to drop. A cooler body temperature is associated with sleep onset...
Finish your exercise at least 3 hours before bedtime. Late afternoon exercise is the perfect way to help you fall asleep at night.
Avoid stimulants such as caffeine and nicotine close to bedtime. They can keep you awake. Caffeine products, such as coffee, tea, colas and chocolate, remain
in the body on average from 3 to 5 hours, but they can affect some people up to 12 hours later. Even if you do not think caffeine
affects you, it may be disrupting and changing the quality of your sleep. Avoiding caffeine
within 6-8 hours of going to bed can help improve sleep quality.
If you continue to have sleep problems:
a sleep diary and talk to your doctor. Note what type of sleep
problem is affecting your sleep or if you are sleepy when
you wish to be awake and alert. Try these tips and record your sleep and sleep-related activities in a sleep diary.
If problems continue, discuss the sleep diary with your doctor.
There may be an underlying cause and you will want to be properly diagnosed. Your doctor will help treat the problem or may
refer you to a sleep specialist.
Losing Sleep Over
the State of the Economy?
Recession Has Millions of Americans Tossing and Turning, Poll Shows
Reviewed by Louise Chang, MD
March 2, 2009 - Worried you
might lose your job? Searching for a new one? Concerned that your retirement funds are dwindling? In the mood, but lack the
If you answered yes
to any of those questions, you may be among the nearly 1/3 of Americans who are losing sleep because of personal finances, job fears, and the nightmarish state of the economy.
According to a new poll
by the National Sleep Foundation:
- 16% of Americans say their sleep
has been disturbed at least a few nights a week in the past month because of personal financial concerns; 15% cite worries
about the economy and 10% express concerns about employment.
- 8% report losing sleep because of health care costs, 6% toss
and turn because of the wars in Iraq and Afghanistan, 3% blame their lack of shut-eye on the threat of terrorism, and 3% lose
sleep over global warming.
The poll suggests that inadequate
sleep is associated with unhealthy lifestyles and that not getting enough sleep has a detrimental effect on health and safety.
"It's easy to understand why
so many people are concerned over the economy and jobs, but sacrificing sleep is the wrong
solution," says David Cloud, chief executive officer of the National Sleep Foundation. "Sleep
is essential for productivity and alertness and is a vital sign for one's overall health."
About 40% of Americans agree
that sleep is as important as diet and exercise to overall health, yet the poll says only 32% of people with sleep problems discuss their
concerns with doctors.
According to the poll, 2 out
of every 10 Americans sleep fewer than 6 hours a night.
It also finds that:
- 28% of everyone surveyed reported that they have driven when
drowsy at least once a month in the past year.
- Nearly 90% surveyed reported they had insomnia at least a few
nights a week in the past month.
"With the economy worsening,
we are seeing patients in our clinic who have told us that they would not be returning for treatment because they or a family
member have lost their jobs, and they are concerned about costs," says Meir Kryger, MD, director of research and education
at Gaylord Sleep Services.
So what are you supposed to
do if you’re having trouble sleeping?
- Use your bedroom only for sex and sleep.
- Keep a regular bedtime.
- Make sure your bedroom is dark, cool, and quiet, and that you've
got a comfortable sleep surface, pillow, and bedding.
- Turn off the TV, and put the laptop away.
- Exercise as much as you can, but make sure you stop at least 3 hours before bedtime.
- Avoid foods and drinks high in caffeine for at least 8 hours before bedtime; stay away from alcohol, which disturbs sleep.
source site at Web Md: click here
6 Things You Can Do To Get A Better Night Sleep
By Jesse Cannone, CFT, CPRS
Let’s face it… we live in a “go-go”
world! Our lifestyle is harried, our food is fast and statistics now show it’s taking a toll on one of the most important
parts of our life - our sleep.
The 2002 National Sleep Foundation (NSF) Sleep in America poll
found that 74% of American adults are experiencing a sleeping problem a few nights a week
or more, 39% get less than 7 hours of sleep each weeknight and more than 1 in 3 (37%) are
so sleepy during the day that it interferes with daily activities.
fast paced way of life is getting the best of us. What about you?
Answer True or False?
1. 5 hours of sleep at night is good enough.
2. It's ok to skimp on sleep during the work week as long as you make up the
time over the weekends.
3. The effects of sleep deprivation are short-term (e.g., darkness under the eyes and dull &/or splotchy skin after a bad night's sleep) and
has no effect on long-term health.
4. Drinking caffeine early in the evening doesn't affect sleep.
5. Keeping a TV or computer in the bedroom has no effect on sleep.
6. The amount of sleep I get has nothing
to do with my weight.
If you answered “true”
to 2 or more questions you may need to make a few changes in order to achieve the highly coveted “good” night’s
sleep and keep yourself in optimal health.
Experts suggest that most people need between 7 and 9 hours of sleep each night but that doesn’t apply to everyone. Some people only require 6 hours while those who
are more active or have an illness may require more.
do you know if you're getting enough quality sleep? Those who are sleep deprived often look the part. Dark circles and the “sleepy”
look are common, but they also can have unpredictable moods, drowsiness during the day, have difficulty concentrating, weak
immune systems, recover poorly from injury and get sick more often. Sounding a little too familiar?
In fact, poor sleep has been found to impair
the ability to perform tasks involving memory, learning and logical reasoning. This may contribute to mistakes or unfulfilled
potential at school or on the job as well as strained relationships at home.
Even more disturbing
, inadequate amounts
have been linked to an increased risk of diabetes, high blood pressure, weight
gain, obesity, heart disease and depression
, to name just a few.But what if you go to bed early
have every intention on logging in your 7-9 hours but only to lie awake watching the clock…eyes wide open?
Well, there are several simple adjustments you can make to stack the cards
in favor of a better night’s sleep.
watching TV before bed…especially in bed!- The bed should be reserved for 2 things…sleep and romance…not Desperate Housewives or football!
Research shows that those who experienced the most sleep
disturbances had televisions in their bedrooms and used the TV to fall asleep.
Try a different pillow or mattress. It’s scary to think how long some of
us have been sleeping on the same pillows and mattresses for years and years.
Does your mattress provide the support you like?
Do you wake with your back aching?
Is there enough room for you and your sleep partner?
Do you sleep better, or worse, when you
sleep away from home?
hese are all things to ask yourself to determine if your mattress could
be the “sabotager” of your good night’s sleep
. Or more simply, just replacing
your pillow with a new, fresh, higher quality version could be all that you need.3) Avoid caffeine late in the day.
Did you know that even a small amount of caffeine even 10-12 hours before bedtime can cause
problems falling asleep!
ry eliminating the tea, soda and even chocolate
and see if sleep
to relaxing music.
Establishing a relaxing
bedtime routine, such as listening to music, could be just the thing you need to signal your body it's time to sleep
, dim the lights and throw some slow
jazz or purchase a “relaxing
sounds” CD to help slow your mind and body down for an evening of peaceful sleep.5)
Try mind- body techniques.
After an action-packed day, your
brain and body need to unwind and detox before sleep
can occur (a.k.a.
you need to chill!
reate a “ritual” for bedtime - take a bath, meditate
, do some easy stretches or yoga. Try to do your “ritual” in the same way, in the same place, at the same time
he repetition will trigger your mind and body that it's time to relax
.6) Try a natural sleep
For many people, while the above tips and suggestions may help, it often isn’t enough. If you're
one of those people who really have a hard time getting to sleep and staying asleep, you may want to try a natural sleep aid.W
hile over the counter sleep medications
may help you fall asleep, they can't be taken long-term and have risky side effects. A sleep
aid that uses natural ingredients is a better approach to getting a solid night’s sleep