licht.wissen 19 No. "Impact of Light on Human Beings"

<strong>licht</strong>.<strong>wissen</strong> <strong>19</strong>
<strong>Impact</strong> <strong>of</strong> <strong>Light</strong> on Human Beings
<strong>Light</strong> therapy
Biologically effective light is also used in medicine. Seasonal affective disorder
(SAD), a mood disorder that occurs in the darker months <strong>of</strong> the year, is
already being successfully treated with light. Studies show that light therapy
is also effective against non-seasonal depression and other ailments.
Trees lose their leaves, storks fly south,
hedgehogs hibernate. Only human beings
think they can defy the seasons. Clearly,
a life ruled by nature does not fit easily
into our industrialised world. <strong>No</strong> employer
would accept employees working to a
schedule determined by biorhythms. As a
result, many people struggle through autumn
and winter in noticeably low spirits.
Seasonal affective disorder (SAD)
Lack <strong>of</strong> light is indeed a serious problem:
if insufficient natural light is available,
5–20 % <strong>of</strong> all people develop veritable
“deficiency symptoms”. Symptoms such
as greater need for sleep, lack <strong>of</strong> energy,
mood swings and even depression can
develop during winter months into SAD, a
condition that needs to be treated.
US scientists have been studying this
phenomenon since the early <strong>19</strong>80s. What
distinguishes SAD from other forms <strong>of</strong>
depression is mainly the fact that symptoms
subside as the days grow longer in
spring but then return again in autumn.
Ravenous appetite from lack <strong>of</strong> light
In contrast to other depressive patients,
people affected by SAD do not suffer from
insomnia. On the contrary, they go to
bed earlier. Yet they still have difficulties
getting up. <strong>No</strong>r do they lose their appetite,
which is a typical symptom <strong>of</strong> depression.
They may actually develop cravings, especially
for carbohydrates such as chocolate,
potato products or bread.
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So scientists believe there may be several
causes for SAD: malfunctioning photoreceptors
on the retina might be one <strong>of</strong> them,
an insufficiently pronounced sleep/wake
rhythm could be another.
[33] At the doctor’s, in hospital or at home:
light therapy is an effective and straightforward
safeguard against seasonal affective are less able to adapt to the shorter days
One probable factor is that SAD patients
disorder. <strong>of</strong> winter. This throws their internal clock 33