During peri-menopause, approximately two thirds of all women experienced the most common changes, called vasomotor, meaning that they result from a change of the circulation (such as increased blood flow, temperature, and heart rate).
This is commonly known as a hot flash or flush. A woman having a hot flash becomes very warm and may perspire with the possibility of a cold chill following.
Induced menopause (through surgical removal of the ovaries or when ovaries are damaged through certain drugs or x-rays), as well as early natural menopause (before age 40) is usually associated with a sudden onset of acute vasomotor symptoms.
These women may need higher doses of estrogen hormone than a woman whose menopause experience is more gradual, to not only provide relief but also care for the greater risk for health problems later in life since they will spend more years without the protective effect of estrogen.
While the hot flashes present no inherent health hazard, they can certainly be annoying, and are sometimes even debilitating.
The brain releases a hormone, GNRH, in surges due to the low level of estrogen. These sudden releases cause the hot flash. This periodic release of GNRH is generally worse at night.