It is a known fact that too less light -– especially too less natural light –- can lead to depressions. Especially in the dark time of the year the gloomy mood is progressing. The missing sunlight is having a negative effect on our mood and enhances the seasonal affective disorder (SAD). But, it is a new finding that too much light also is able to enhance depressions. A study of American scientists of Ohio State University unveiled this fact.
Lights out during sleep
A lot of people do as follows: sleeping with the window open and also open shutters to let enough air into the room. But, not only air is arriving but also dim light from the outside.
American scientists have found out that sleeping with dim light may lead to depressions. The scientists of the Ohio State University used for their study female, sterilized Siberian hamsters to exclude possible hormonal triggers of depression.
The animals were divided into two groups. One group lived their normal rhythm for eight weeks. 16 hours per day with 150 lux and 8 hours of darkness. The second group lived four weeks 16 hours with 150 lux and 8 hours with 5 lux per day. These 5 lux for example comply with the light of a TV in the dark.
After this, the animals spent one, two or four weeks in the dark. It was apparent that the animals that were exposed to dim light during the night for four weeks showed little interest on dim light. This is a sign for depression. But, only two weeks of a normal sleeping rhythm reversed this effect.
Possible reason for this is the so-called tumor necrosis factor. This is a molecule that in the brain is responsible for the development of depressions.
The scientists guess that a human being that watches TV until very late or where street lamps are shining into the bed room show the same effects like the hamsters. This makes the sleep biologic recommendation more than clear: lights out during sleep!
Even a glimmering TV or a diffuse light outside are enough to trigger this effect. During sleep, the body needs absolute darkness to regenerate. Due to the scientific evaluations and thoughts it is advisable to avoid too much light during sleep in any case. On the other hand, the illumination in towns is constantly growing. Out of this reason it is important to take care that no light impulses from outside may enter the bed room. Meanwhile, there are perfect darkening systems.
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