that the only effect of
lack of sleep was tiredness. His group showed
that sleep restriction
in healthy young men
led to signs of insulin
resistance
which can
lead to type
2 diabetes.
The mechanism behind
these effects
seems
to
involve two
important
hormones
that regulate hunger
(ghrelin)
and satiety
(leptin).
The group
who
slept
fewer hours had an
increase in the levels of
ghrelin and a decrease
in the levels of leptin
increasing their appetite1.
Indeed, many studies
have found that people who sleep poorly
are more susceptible
to develop obesity and more risk of developtype 2 diabetes.
ing diabetes.
One study showed that
people who slept for 5
Is sleep duration more
hours each night had important than sleep
an increase of 3.6% quality? Sleep qualin body mass index. ity is just as important
Interestingly, the group as sleep duration. The
that slept fewer hours same effect of reduced
had a preference for insulin sensitivity was
fatty substances and found in people who
carbohydrates and con- slept 7 to 8 hours but
sumed more calories were prevented from
through foods of this entering deep sleep.
type. Reducing sleep- This effect could be
ing time has a power- explained by the fact
ful effect on cells in our that the onset of slowbody.
wave sleep coincides
For instance a study with hormonal changes
by Tasali, Brady and in our body.
van Cauter demonstrated that four
nights of just
4.5 hours
of sleep
reduced
t h e
reducing sleeping time
insulin
has a powerful effect
sension cells in our body
tivity of
fat cells2.
It means
that these
people have
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