Cause of Hot Flushes

Dear Dr. Mirkin: What causes hot flushes at menopause?
Hot flushes are caused by a down-setting of the
temperature-regulating part of the brain. When you have an
infection and your temperature rises above 100 degrees, you
sweat to cool off. At the time of the menopause, you still sweat
when your temperature rises, but at lower than normal
temperatures, such as when you go from 97 to 98 degrees. Hot
flushes persist for five years in 60 percent of women and for
more than 15 years for ten percent.
A hormone called norepinephrine causes a woman's brain
to think that her body is overheating, even if it isn't. She
then flips open the blood vessels in her skin, giving her the
feeling of a rush of heat, and she starts to sweat. Clonidine, a
blood pressure medicine, lowers norepinephrine and blocks hot
flushes in some susceptible women. We still do not have any
good drugs to effectively lower norepinephrine levels in the brain,
but here at least is a lead for future researchers.
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