EARLY TO BED, EARLY TO RISE?

Updated September 22, 1998

News Release: Journal of Sleep and Sleep Disorders Research

Contact: Charles Wilson at 507-287-6006

EARLY BIRD OR NIGHT OWL?
Rochester, MN (September 15, 1998) -- according to a study published in the latest issue of the journal SLEEP , there may be a genetic reason why some people seem to be “night owls” and other “early birds.” Researchers from Stanford University and the University of Wisconsin have identified a mutation on a gene that seems to be and indicator for what they call “morningness-eveningness,” or a person’s preferred time of day for doing things.

CLOCK GENE DETERMINES MORNING OR EVENING PREFERENCE
Researchers studied 410 adults in this study. The subjects were given a questionnaire designed to determine the time of the day at which they preferred doing certain tasks. This questionnaire, named the Horne-Ostberg questionnaire in honor of its developers, has been used by researchers for almost 20 years. By totaling their Horne-Ostberg scores, researchers were able to determine whether the subjects prefers the morning or the evening. At the same time, the researchers studied one particular gene, called the CLOCK gene, in each of the subjects. When the researchers compared the results, they found that subjects with a specific variation of CLOCK gene were most likely “evening people.”

According to one of the study’s authors, Dr. Emmanuel Mignot, the study refers to circadian rhythms, or a person’s internal clock. This internal clock controls behaviors like sleeping and waking, and is tied to the 24-hour daily dark-light cycle.

SOME PEOPLE HAVE SLIGHTLY ALTERED CIRCADIAN RHYTHMS
Prior to the study, researchers had already identified several genes that seem to regulate human circadian rhythms. But this study confirms what researchers had suspected: that people with a specific variation of CLOCK gene have slightly altered circadian rhythms. “People with altered circadian rhythms may not be ready to go to bed when society tells them to. And they may be getting out of bed too early or too late,” explained Mignot.

RESEARCHERS HOPE WORKERS OF THE FUTURE WILL ADJUST SCHEDULES
The researchers hope that some day, humans may be able to test their genetic make-up to determine their healthiest schedule. Genetic reasons may explain why some people aren’t productive workers at 8:00 a.m., and why others arenšt productive at 4:30 p.m. Ideally, Mignot says, “workers of the future will be able to adjust their schedules so as to optimize the time they spend at work.”

MAY EXPLAIN WHY CERTAIN PEOPLE SUFFER INSOMNIA
Mignot says that this finding is also an important discovery in the field of sleep disorders, because it may explain why certain people suffer from insomnia. “If a person’s internal clock is telling them that they should be going to bed at 1:30 in the morning, it’s no wonder the person can’t get to sleep when they go to bed at 10:30 at night,” he said.

Mignot emphasized that this is the first study to find a relationship between these circadian genes and morningness-eveningness tendencies. The results need to be replicated in order for researchers to confirm their findings.

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