University of Iowa Health Science Relations and
Mark Dyken, MD
Associate Professor of Neurology
First Published: 2004
Last Revised: April 2004
Peer Review Status: Internally Peer Reviewed
What is sleep?
Webster defines it as the natural suspension of
consciousness during which the body restores itself.
To be more precise, sleep is a biological function caused
by the discharge of specific neurons in certain parts of the
brain. It involves an alternate cycle of non-rapid eye
movement (NREM) and rapid eye movement (REM). The cycle
consists of approximately 90 minutes of NREM followed by REM. This
90-minute cycle is repeated three to six times during the night.
However you define it, sleep affects every human
physiological and psychological process.
The mind and body do not shut down during sleep. Quite
the contrary. Sleep permits the brain to consolidate the
day's learning into memory and improves the brain's ability
to learn repetitive skills, such as riding a bicycle. During
sleep, the body does maintenance work--replacing old cells
and re-energizing organs and muscles. The "work" sleep does
for you at night is vital for you to function at your best
during the day.
But society doesn't treat sleep with very much respect.
This is a 24-hour society--shift workers, 24-hour stores,
the Internet. You steal from your sleep hours to add extra
hours for activities. The number of hours the average person
sleeps has been reduced by 20 percent in the past century.
Society has changed, but your body's need for sleep has not.
"We know sleep is necessary for the physical and mental,"
says Mark Dyken, MD, University of Iowa Health Care Sleep
Disorders Center. "All organisms require some form of quiet
state. If we don't give the body enough sleep, it will make
sure that it gets what it needs. Truck drivers and shift
workers have a difficult time getting enough sleep so they
don't fall asleep at inappropriate times."
The body has its own daily rhythms or circadian cycles.
"From approximately 1 to 3 a.m. and 1 to 3 p.m. is when most people tend
to naturally want to sleep. The siesta falls into that rhythm,"
What happens when you don't get the sleep you need? For
one thing you get grumpy. Sleep deprivation also can lead to
increased fatigue, poor attention and motivation spans,
memory lapses, and poor judgment.
What is enough sleep? Dyken says it depends on the
A baby's biological rhythm is very different from an
adult's. Just ask anyone who has raised a child. "They are a
different animal," Dyken says. "Their sleep/awake patterns
can be every three to four hours. That's why so many new
parents wonder if their child will ever sleep through the
"Kids up to age 12 need about 11 hours of sleep each
night. This will probably be some of the best sleep of your
life," Dyken says. Older children and young adults through
their 30s need seven to nine hours of sleep each night.
"At age 40, people begin to notice that their sleep
patterns change. At age 50, major differences are
recognizable," Dyken says. More than 50 percent of Americans
aged 65 and older have a sleep problem. "Older people get
less sleep. They don't necessarily need less sleep, but
pain, medications, stress, and other health factors affect
their sleep. It is part of the normal progression through
What about those occasional times when
you can't fall asleep?
Dr. Dyken says there are two schools of thought on
what to do.
If you haven't fallen asleep in 15 minutes, he suggests
staying in bed. "Have a good relaxing book nearby and read until your
eyes are ready to droop. For some people, it may be some other form
of relaxation they can associate with the sleep initiation process.
It is all part of positive conditioning," he
The other schools of thought suggest that after 15 to 30
minutes of not being able to fall asleep, especially if you are becoming
anxious, you should get up, go to another room and read, engage in
quiet activity, take
a warm bath. Don't let yourself fall asleep in another room,
but return to your bed when you feel drowsy.
"Sleep is an individual experience," Dyken says. "What
helps one person sleep, may not help the next person." He
says most people know themselves well, and after keeping
track of some nighttime routines, can determine what does or
does not lead to a good night's sleep. "If you have a cup of
ginseng tea before you go to bed and that works for you,
fine. It may not work for everyone," he says.
Conditioning, both positive and negative, has an impact
on how people fall asleep and stay asleep.
"People can condition themselves to get ready for a good
night's sleep by creating a psychologically inviting
atmosphere in the bedroom," he says. The bedroom should be
quiet, have a minimum of light and the temperature should be
constant. The bedroom should be used for sleeping, not doing
bills, planning your schedule for the week, or using your
laptop to catch up on e-mails.
Negative conditioning can be a powerful influence on a
person's sleep patterns. "What keeps us awake or wakes us up
can be recurring, negative thoughts." Dyken says.
"If something is bothering you, you are depressed or have
suffered a tragedy, these thoughts can interfere with your
sleep, even when the problems or events are behind you," he
said. Why? "Because it has become part of your sleep
pattern. The pattern must be altered so you can return to a
normal sleep routine."
up later than normal for special events has its
consequences, for adults as well as children.
Sleep loss that accumulates from one night to the next is
called a "sleep debt" or sleep deprivation. Even a modest
loss of sleep, like staying up to celebrate with friends,
can produce a sleep debt when sustained over several nights.
While Dr. Dyken suggests you avoid naps if you have
trouble sleeping at night, he indicated that napping was not
always bad. "You can't really catch up on sleep, but it is
better to take that afternoon weekend nap than to have
missed the sleep completely.
"For every hour of sleep missed, it takes a young person approximatley
24 hours to adjust," he said. Jet lag is an example on a large scale.
"If you travel to London, you will experience a seven-hour
time difference and it will take you a full week to
According to the National Sleep Foundation, there is
increasing evidence that a 15 to 20 minute nap can improve
alertness, sharpen memory, and generally reduce the symptoms
A nap is not a substitute for a full night's sleep. It is
only a short-term fix.
Top sleep disorders
Insomnia - not being able to fall asleep, the
feeling of not having slept well or long enough.
According to a 1996 National Sleep Foundation survey, 49
percent of Americans suffer from insomnia and 75 percent of
them list stress and depression as the reason. Dr. Dyken says insomnia is the number one reason people come to
his Sleep Disorders Clinic.
Short-term insomnia, lasting no more than three weeks,
may be caused by concerns about money or relationships, the
death of a loved one, health problems, boredom, etc.
Long-term insomnia may be attributed to heart disease,
diabetes, asthma, and ulcers, to name a few. Chronic drug or
alcohol abuse, as well as excessive use of caffeine and
sleeping pills, can disrupt regular sleep patterns.
Primary Snoring - loud upper airway breathing
sounds during sleep.
Snoring can sometimes be a symptom of a serious disorder.
When an individual snores loud enough to disturb others, it
is usually a strong indication of sleep apnea.
- Avoid alcohol within two hours of bedtime. Alcohol
depresses breathing and makes snoring more frequent.
- Avoid sleeping pills. They tend to depress breathing
and make snoring worse.
- Lose weight.
- Take medications with care. Be aware of possible side
- Sleep on your side, not on your back.
- Treat allergies or cold symptoms.
Restless Legs Syndrome (RLS) - uncomfortable
tingling or prickling sensation of the legs during sleep.
If you have RLS, the prickling sensation is so
uncomfortable that only massaging your legs or moving them
will help. The discomfort can keep you awake and wake you
up. The discomfort and sleeplessness that follow RLS can
lead to serious psychological distress and depression.
There aren't any cures for RLS, but medications are
available to treat it.
Sleep bruxism - grinding of teeth during sleep.
It occurs in 85 to 90 percent of adults and 50 percent of
children. It leads to severe dental damage in five percent
of the cases.
Sleepwalking - nocturnal walks the sleeper doesn't
It occurs in adults but is most prevalent in children.
Sleepwalkers don't remember their walks, but seem to
navigate surprisingly well. It seems to be a temporary sleep
mechanism malfunction that occurs during the deeper stages
of sleep. It tends to run in families. Most leave
sleepwalking behind at puberty.
- There is no medical intervention.
- Keep habitual sleepwalkers safe from harm by
keeping doors and windows closed and guarded.
Sleep talking - talking while asleep.
Sleep talking can range from a word or two of gibberish,
to an entire speech. The sleeper generally has no memory of
the event. It is harmless, temporary, and can be brought on
by stress or illness.
Is sleep sometimes a
Here are some suggestions to make getting a good night's
sleep a little easier:
- Establish a regular time to go to bed and time to get
up. Follow them consistently - even on weekends.
- Establish a sleep ritual. Do the same things each
evening as you get ready for bed to cue your body to
settle down for the night.
- Don't exercise within two hours of bedtime. Instead
of wearing you out, it will raise your heart rate and
boost adrenalin, making it difficult to sleep.
- Avoid alcohol three to four hours before bedtime.
Alcohol may induce sleep for two to four hours, but after
that can interrupt or disrupt sleep.
- Avoid stimulants like caffeine. They can interfere
with falling asleep and may prevent deep sleep.
- Avoid smoking. Smokers take longer to fall asleep,
awaken more often, and experience disrupted, fragmented
- A light snack may help you fall asleep, but a large,
heavy meal will keep you awake, especially if you suffer
from acid reflux.
- Unwind early in the evening. Try to deal with
problems several hours before bedtime.