| What
is Bright Light Therapy?
Light therapy is a treatment used
for people who suffer from circadian
rhythm sleep disorders. Your body has
an internal clock that tells it when
it is time to be asleep and when it
is time to be awake. This clock is located
in the brain just above an area where
the nerves travel to the eyes. This
area is called the SCN. Your clock controls
the "circadian rhythms" in your body.
These rhythms include body temperature,
alertness and the daily cycle of many
hormones.
The word "circadian"
means to occur in a cycle of about 24
hours. Circadian rhythms make you feel
sleepy or alert at regular times every
day. Some people have a circadian rhythm
sleep disorder. This causes their natural
sleep time to overlap with regular awake
activities such as work or school.Among
other factors, your clock is "set"
by your exposure to bright light such
as sunlight. Exposure to bright light
or "light therapy" is one method used
to treat people with a circadian rhythm
sleep disorder.
The
goal for treating patients who have
circadian rhythm problems is to combine
a healthy sleep pattern with an internal
clock that is set at the right time.
This will allow them to enjoy the benefits
of good sleep. Light therapy can help
someone "re-set" a clock that is off.
Regular sleep patterns help to keep
the clock set at the new time. Light
therapy is only part of a treatment
plan that should be guided by a doctor
who is familiar with sleep disorders.
Light
therapy is used to expose your eyes
to intense but safe amounts of light
for a specific and regular length of
time. In many places, sunlight is not
available at the proper time to be used
as treatment.
What
are the bright light therapy product
groups?
1. Light Box This
is the most common tool that is used
in light therapy. The box houses several
tubes that produce extremely bright
light. It sits on top of a table or
desk and plugs into the wall.
During
a treatment session, you have to keep
within a certain distance of the box.
Usually, you will be about 18 to 24
inches away from it. It does not require
you to look directly into the light.
Instead, you simply face in the direction
of the box.
You
are able to do other activities during
the session. Ideally, you would work
on papers or read something that is
in the area being lit up. This will
allow the light to be received by your
eyes. Your body takes in this information
and uses it to regulate the rhythms
that control when you sleep and when
you wake. Earlier models of light boxes
put out 2,500 to 5,000 lux of light.
Lux is a measure of how much light falls
on your eyes. These sessions could take
two or three hours. Now, many boxes
produce 10,000 lux of light. This allows
sessions to take as little as 15 to
30 minutes. M
ore
than one session may be needed each
day. It depends upon your body, your
need, and the strength of light being
used. The key is to use the light at
the right time of day and for the right
amount of time. This is based upon the
sleep disorder you want to correct.
New models are also safer, protecting
you from harmful UV rays. Some models
are now focusing on a specific bandwidth
of light. Light boxes can be purchased
in a variety of makes and models. Some
are now being made much smaller so they
are easier to take with you. General
prices range from $200 - $500 per light
box.
2.
Desk Lamp and Floor Lamps This
serves the same purpose as a light box,
but it is made to look like a normal
lamp. It blends in better when used
in an office setting.
3. Dawn Simulator These lights
gradually make a dark room brighter
over a set period of time. This is meant
to mimic the sunrise. Some people may
find that this helps them wake up in
the morning. Models may also slowly
dim to copy a sunset.
What
is S.A.D.? (Winter Blues)
Many people who live in the northern
latitudes experience the Seasonal Affective
Disorder (SAD) or winter blues to some
extent. Some can muddle through the
lethargy, fatigue and lack of motivation
felt during autumn and winter. For those
suffering from SAD, it is difficult
to make it through the dark season.
Over
20 years ago, mental health researchers
showed that Winter Blues, or Seasonal
Affective Disorder (SAD), also called
Seasonal Depression, could be treated
with light therapy. Today, light treatment
is the modality of preference by physicians
for the treatment of SAD. About 10%
of the population of northern countries
suffer from SAD. The main signs are
fatigue, excess sleeping, withdrawal,
and carbohydrate craving during the
fall and winter months.
Seasonal
affective disorder or SAD is a form
of depression that occurs mostly during
the fall and winter months, when days
shorten and sunlight decreases. One
of the characteristics of this particular
form of depression is its seasonal aspect.
In many of the articles dealing with
this subject, you will also find the
expressions "winter depression"
and "winter blues". Night-shift
workers or people who work or live in
a poorly or badly lit place can also
suffer from SAD, even during summer.
Usually, women tend to suffer from this
type of depression more than men. Children
and adolescents are particularly susceptible
to the effects of SAD or Seasonal Affective
Disorder. The depressive symptoms appear
more often during the fall months and
tend to disappear come late winter or
early spring.
The
seasonal onset of this depression seems
to occur in the late summer
or fall, especially
in northern latitudes, when the days
grow shorter. It subsides in the spring
when the weather improves and the days
grow longer. This depression is often
accompanied by general sluggishness,
irritability, carbohydrate craving and
reduced libido. It is important, however,
to consider that the seasonality may
be caused by other factors, notably
psychological (eg. the return to school
in the fall and the anticipation of
summer vacation in the spring). For
this reason, it is always a good idea
to consult with a health professional.
The
magnitude of seasonal difficulties may
vary from one person to another. For
SAD sufferers, it is a relief to know
that depression is no longer linked
to a weakness of character, but to an
alteration of our brain chemistry.
Many
people treated by Dr Norman Rosenthal
at the NIMH (National Institute Mental
Health) in Maryland, USA have told how,
prior to being diagnosed with SAD, they
felt lazy, worthless, and immature.
Just knowing that the disease has a
name, a description and that there is
an affordable and effective non-invasive
treatment, is a relief in itself.
Who
gets it?
Bright light therapy is used for people
who suffer from circadian rhythm disorders.
The time of day when the light is used
will depend upon the disorder it is
meant to correct. These disorders include
the following:
Delayed Sleep Phase disorder
This causes people to fall asleep much
later at night than is normal. As a
result, they also wake up later in the
morning. This sleep pattern can interfere
with their schedule of activities for
the day. To correct delayed sleep phase,
light treatment takes place during the
early morning hours.
Advanced
Sleep Phase disorder
This causes people to fall asleep much
earlier at night than is normal. They
also wake up earlier in the morning.
To correct it, light treatment takes
place early at night.
Free-running
or Non-24-hr Sleep-Wake rhythm
People with this disorder fall asleep
at a different time each day. For example,
you may fall asleep at 10 p.m. one day,
Midnight the next day, 2 a.m. the next,
etc. This most often occurs in people
who are blind. Light therapy may help
blind people, even if they can't perceive
visible light. Studies show that light
treatment may be useful in the early
morning hours.
Jet
Lag
Jet lag causes people to have problems
with sleep when they have crossed many
time zones on a flight. Light therapy
in the morning may help when traveling
east. For travel to the west, bright
light in the evening may help reduce
jet lag.
Shift
Work
This sleep disorder occurs due to a
work schedule, such as night shift,
that takes place during the time when
most people are sleeping. This schedule
requires you to work when your body
wants to sleep. Then you have to try
to sleep when your body expects to be
awake. Correcting it can be a hard problem
to solve. Changing work schedules, days
off, and social activities can alter
your exposure to light from day to day.
Frequent changes in your sleep times
make it hard to re-set your internal
clock. In general, using light treatment
in the evening should help someone who
regularly works nights. In this case,
you would also want to avoid daylight
when you come off work and go to bed.
Dark sunglasses or special goggles can
help.
Reviewed by Norman J. Wilder, MD
Updated on May 11, 2006, www.sleepeducation.com
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