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Scientists have found increased
blood levels of stress hormones in people with
chronic insomnia, suggesting that these individuals suffer
from sustained, round-the-clock activation of the body's system
for responding to stress.
For this reason, the researchers suggest,
doctors who treat insomnia should go beyond improving the
quality or quantity of their patients' sleep and seek to reduce
this hyperarousal, which is a risk factor for both
psychiatric and medical illness.
Investigators monitored the sleep of 11
patients with insomnia and 13 people without sleep disturbances
(the "control" group). Blood was collected every
30 minutes for 24 hours, and levels of stress hormones --
adrenocorticotropic hormone (ACTH) and cortisol were monitored.
Average levels of both hormones were significantly
higher in the insomniacs than in the control group.
They found that the insomniacs with the
highest degree of sleep disturbance secreted the highest amount
of cortisol, particularly in the evening and nighttime hours,"
Vgontzas said in a prepared statement. This means that insomniacs
are experiencing hormonal
changes in their bodies, which prevents them from
sleeping.
The investigators propose that the physical
mechanism of chronic insomnia differs from that of sleep loss,
with chronic insomnia being a disorder of hyperarousal present
throughout the 24-hour sleep/wake cycle. Increased production
of stress hormones is likely to lead not only to depression,
but also to high blood pressure, obesity and osteoporosis.
This information could help doctors who
are treating insomniacs
refocus their therapeutic goals. Instead of aiming
to simply improve nighttime sleep, doctors may now work to
decrease the levels of physiologic
arousal.
Journal of
Clinical Endocrinology & Metabolism August 2001; 86:3787-3794
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