Mechanism of Hot Flash
Hot flash is thought to be triggered by low levels of estrogen caused by the declining ovarian function that occurs during menopause. The hypothalamus in the brain, which controls the body temperature becomes confused and as a result heat releasing mechanism is triggered. The phenomenon is caused when the blood vessels (capillaries, veins, arterioles) all dilate which causes heat to dissipate off. In addition to this the sweat glands release more sweat to cause cooling.
According to Sue Davis, "There can be just hotness in the face, or some women have total body heat. They go red, they start sweating, and they're dripping under their armpits ... some women wake up several times a night drenched in sweat."
The duration of a hot flash can extend anywhere between 3 to 5 minutes. But there are instances where an episode had stretched to about an hour or so. The duration and intensity of hot flashes varies from one woman to another.
