Extensive video gaming, disruption of sleep
patterns, circadian rhythms... and obesity. Is there a connection?
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Looking for Links Between Sleep Patterns and
Obesity
By Alfredo Flores August 16, 2007
While many experts believe that weight gain and obesity are caused
chiefly by too much eating and too little physical activity, additional factors
may help explain the dramatic increase in obesity worldwide.
Geneticists Molly Bray and Martin Young at the Children's Nutrition
Research Center (CNRC),
Houston, Texas, are exploring human circadian rhythms and their effect on
obesity. The CNRC is operated by Baylor College
of Medicine in cooperation with
Texas Childrens
Hospital and the Agricultural Research Service (ARS), the U.S. Department of Agricultures chief
scientific research agency.
Circadian rhythms include sleep-wake cycles controlled by an inner
biological "clock" on roughly a 24-hour schedule. Biological rhythms, such as
the sleep-wake cycle, are central to all aspects of life. Because of this
circadian clock, sleepiness is not solely the result of passing time. It's
influenced by the length of time since a person previously awoke from
sufficient sleep and the internal circadian rhythm, so sleep and wakefulness
can occur at different times of the day or night.
Recent reports suggest that disruptions in sleep patterns in children
may be linked to todays round-the-clock lifestyle, caused in part by
increased sedentary entertainment options like video games, television and the
Internet. Such nonphysical activities have been associated with increased body
fat and altered metabolism.
Abnormal sleep/wake patterns may change circadian clocks that normally
allow cells to anticipate variations in the outside environment, such as
changing levels of nutrients (glucose, fatty acids and triglycerides) and
hormones such as insulin.
Young focuses on the circadian clock's effects within heart muscle
cells and has published several papers on the topic, including a recent review
in the September issue of Sleep
Medicine. Bray has extended the research focus of Youngs work
into the area of obesity, and they published their initial work in Obesity
Reviews earlier this year.
Bray and Young are both optimistic that identifying the role of the
circadian clock mechanism within fat cells may lead to improved understanding
of the increasing obesity problem and the timing of obesity therapies.