however, there are exceptions, and many people are able to
function without sleepiness or drowsiness after as little as
six hours. Others can’t perform at their peak unless they’ve
slept 10 hours. Note that anything less than five minutes to
fall asleep at night means you’re sleep deprived.
Circadian clock. The circadian clock
coordinates our behavior with daily and
seasonal changes in the day/night cycle. The
internal clock is reset as we sense external
time cues when the environment changes. In short, we
develop a sleep pattern that is almost clock-like, which is
why, after a hard work week, people can’t sleep in on the
weekends no matter how hard they try. New schedules
must be adapted to.
Light. Light can affect sleep. It does so both
directly, by making it difficult for people to fall
asleep, and indirectly, by influencing the timing
of our internal clocks. Due to the invention of
the electric light bulb, we are now exposed to much more
light at night. This affects our sleep patterns. Exposure to
light in the late evening tends to delay the phase of our
internal clock and leads us to fall asleep later than we
would in a more natural-light setting.
Chemicals. Many common substances
affect both quantity and quality of sleep. These
include caffeine, alcohol, nicotine, antihista-
mines, prescription medications and antidepres-
sants. The human brain stores an important sleep-related
chemical called adenosine when we are awake. Caffeine,
the world’s most widely used drug, blocks the adenosine
receptors in different parts of the brain. Because these
nerve cells cannot sense adenosine, they maintain their
activity and we stay alert.
Environment. There are several
variables that make up your sleep
environment. They include light, noise
and temperature. By being aware of the
factors in your sleep environment that put you at ease
and eliminating those that may stress or distract you,
you can set yourself up for the best possible sleep. ❏
Sleep. Sleep is
one of the basic
necessities of life.
It is as import-
ant for our well-being as food,
water and air. Important as air?
That’s right, and most of us
take sleep for granted. Modern,
industrialized society has
allowed our food to be pumped
full of additives, our water
riddled with chemicals and
the air we breathe polluted.
And, the stress of daily life has
begun to deprive us of sleep.
The coffee industry is now a
30-billion-dollar-a-year industry. Why? To feed the sleep
deprived the most widely used
drug in the world, caffeine.
Risk. If you are
you might recog-
nize the negative
effects. Without sleep, your
body is being run down. Some of the repercussions of
sleep deprivation include a weakened immune system,
higher risk of disease and a shortened lifespan. This
should raise red flags, right? But humans have a track
record of waiting until it is too late.
Sleeping awake. When we are sleeping,
we may seem dead to the world, but our
brains are still very active. For centuries,
doctors believed that sleep was a period of
brain inactivity, yet in the past 60 years, research has
shown that the brain is still functioning at a high level.
Some functions of the brain and body are actually more
active during sleep than when we are awake.
Rapid eye movement. There are five
different stages of sleep, with the fifth being
rapid eye movement, better known as REM
sleep. REM sleep accounts for about 25
percent of the total sleep time for adults. It occurs
in intervals during the night and is characterized by
movement of the eyes. REM sleep is closely related to
increased dreaming and body movements. During REM,
the pulse and breathing rate are also heightened. Certain
types of eye movements during REM sleep correspond to
specific movements in dreams, suggesting at least part of
the dreaming process is comparable to watching a film.
In the REM cycle, your muscles become paralyzed. When
this cycle of sleep is skipped and you get stuck in
non-REM sleep, there is a possibility of sleepwalking.
Dreams. Dreaming occurs all throughout
the night in each of the five cycles of sleep.
Most dreams occur in the REM stage, and
these dreams tend to be more vivid. It is in
the non-REM stage that all night terrors occur. There are
varying explanations for why people dream, what dreams
mean and their contribution to human health, but they
are still somewhat of a mystery to scientists.
Amount. Thirty million Americans are sleep
deprived, and 20 percent of those get less
than six hours of sleep a night. Healthy
adults need seven to nine hours of sleep;
ABOUT THE IMPORTANCE OF SLEEP