Ahh, yes. Those blissful Sunday
mornings when the internal clock snaps us wide awake before
eight, but the realization that we can drift gently back
to sleep snuggles into our conscience like a fuzzy, warm
blanket. Sure, there may be a busy day of chores ahead,
but thanks to a new study, we can sleep in without a hint
of guilt, knowing that any lost z's might encourage the
expansion of a waistline that manages to grow quite efficiently
on its own.
YIN-YANG
HORMONES
Published in the December 7 issue of the Annals of
Internal Medicine, the results of University of
Chicago researcher Dr Eve Van Cauter's investigation
into the effects of sleep deprivation on appetite made
international headlines. Twelve healthy young men were
put on a two-day regime of 10 hours of sleep a night,
then six weeks later they were limited to four hours
of sleep for two nights. The goal was to assess levels
of two hormones that affect appetite after each regime.
According to Dr Van Cauter, "Leptin and ghrelin represent
the yin-yang" of chemical messengers that inform the
brain about appetite. Leptin suppresses the appetite
in response to food intake while ghrelin is a powerful
appetite stimulant.
Besides being very cranky, the
men who'd endured only four hours of sleep reported
a 24% increase in "hungriness." Even more concerning
was the foods that they craved, which included not-so-healthy
choices like potato chips, salted nuts and simple starches.
Hormone levels may be at the root of their hunger, as
the sleep-deprived group showed a statistically significant
24% increase in ghrelin, combined with an 18% decrease
in leptin. As Dr Van Cauter kindly translates, "we think
sleep deprivation probably signals a need for additional
calories."
SLEEP
MORE, WEIGH LESS
The implications of this finding are profound considering
the current obesity epidemic. As free time continues
to diminish in our increasingly all work, no play society,
getting those eight hours is a luxury many of us can't
afford. In fact, there's already evidence that lack
of sleep leads to weight gain. According to Dr David
Jenkins, a professor of nutritional science at the University
of Toronto, "studies have shown that shift workers are
generally heavier [than their nine-to-five counterparts],
and have the increased cardiovascular risk factors that
come with this." Keeping this in mind, we can all snuggle
back into our warm blankets secure in the knowledge
that we're not wasting time, but conserving future healthcare
dollars.
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