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Lack of exposure
to sunlight might explain why sleep disturbances grow more
common as people age, researchers in Japan suggest.
In a study of 10
nursing home residents with insomnia, investigators found
that increasing the residents' exposure
to light improved their sleeping patterns.
The dose of brightness
also increased their production of the melatonin, a
hormone believed to help regulate sleep. Some, but not all,
research suggests melatonin production declines with age,
and that melatonin supplements may combat insomnia.
The researchers
then exposed the patients to 4 hours of bright, artificial
light at midday for 4 weeks -- roughly equal to the normal light
exposure of the young control group. The investigators found
that the extra light sent the elderly patients' melatonin
production to a level similar to the young group's,
and improved their sleep quality.
Journal
of Clinical Endocrinology and Metabolism January 2001;86:129-134
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