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.