Poor Sleep Alters Hormones
That Influence Cancer Cells
By Sid Kirchheimer
Reviewed By Michael Smith, MD
on Wednesday, October 01, 2003
WebMD
Medical News
Oct. 1, 2003 -- A new study shows that how well you sleep
may determine how well your body fights cancer -- and may
help explain how mental well-being plays into cancer recovery
and progression.
After analyzing previous studies, Stanford University psychiatrist
David Spiegel, MD, and colleague Sandra Sephton, MD, say that
sleep problems alter the balance of at least two hormones
that influence cancer cells.
Sleep, Hormones, and Cancer
One is cortisol, which helps to regulate immune system activity
-- including the release of certain "natural killer"
cells that help the body battle cancer. Cortisol levels typically
peak at dawn, after hours of sleep, and decline throughout
the day.
Spiegel tells WebMD that night shift workers, who have higher
rates of breast cancer than women who sleep normal hours,
are more likely to have a "shifted cortisol rhythm,"
in which their cortisol levels peak in the afternoon. At least
two studies show those women typically die earlier from breast
cancer.
"We also found that people who wake up repeatedly during
the night are also more likely to have abnormal cortisol patterns,"
he says.
Cortisol is the so-called "stress" hormone triggered,
along with others, during times of anxiety and may play a
role in the development and worsening of cancer and other
conditions.
The other hormone affected by sleep is melatonin. Produced
by the brain during sleep, melatonin may have antioxidant
properties that help prevent damage to cells that can lead
to cancer.
In addition, melatonin lowers estrogen production from the
ovaries. Thus, a lack of sleep leads to too little melatonin.
This series of events may expose women to high levels of estrogen
and may increase the risk of breast cancer.
Spiegel says that women shift workers who are up all night
produce less melatonin.
"There's a definite hormonal pattern that is affected
by sleep that in itself, can predict a more rapid progression
of cancer," he tells WebMD.
"Getting a good night's sleep is fairly simple, if you
allow yourself to do it. The big problem for cancer patients
is they take too much on themselves and don't give enough
time to help their bodies cope with the illness. They're worried
about burdening their families and fulfilling their usual
obligations."
And that's the real message of his study, in the October
issue of Brain, Behavior and Immunity. It indicates the importance
of good sleep as one of several mind-body factors that might
influence cancer outcome.
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