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Hot Flash
Did I just have a hot flash?
Hot flashes are the often a woman's first clear-cut
sign of perimenopause.
What do they feel like?
There's tremendous individual variation between women with
their experiences. An aura may precede the flash, and usually a
flush follows along with post-flash/flush symptoms.
Auras
The heart speeds up. There can be headache or pressure.
Nausea and a sensation in one spot of the body are also felt, by
some.
The Flash.
A heat wave starting usually in the head and neck flows over the
body.
The Flush
Reddened skin will be seen in fair women. The skin temperature goes up between 1 and 7 degrees. Sweating, especially on the back of the neck, chest, or upper lip is common. Heart palpitations. The woman may remove clothing.
Post Flash/Flush
Chilling, dizziness or anxiety.
How To Be Certain
About 50% of women describe their flashes as hardly noticeable. Fitting the general pattern of hot flash is the only way to know. Repeated flashes are also a clue. There are no tests. Some doctors use FSH (follicular stimulating hormone) tests. But, it does not rise until a woman is close to completing menopause. Hot flashes may start much earlier.
Other diseases and condition can mimic hot flashes of menopause. The most common are: panic/anxiety attacks, hyperthyroid, insulin reaction, various medications, alcohol, and tuberculosis.
The Physiology Of A Hot Flash
A gland in the brain called the hypothalamus starts hot flashes. It regulates temperature in the body. It is also involved in regulating the menstrual cycle.
The hypothalamus is like the body's thermostat. During a flash, the thermostat suddenly gets reset down, not up. Your body is like the house and the hot flash is like the heating/air conditioning system. So somebody suddenly turns the thermostat (hypothalamus) way down and demands a much lower temperature in the house (body). Only this heating and cooling system (hot flash) responds by opening the windows. It cools by causing heat to escape from the warm (98.8 F) house to the cooler outside world.
So how does a hot flash "open the window"? The blood vessels near the skin expand. Coupled with the heart pumping faster, the body can bring much blood near the skin's surface. This is why her skin may look red. Closer to the surface, the outside world will cool it down from her core body temperature. This cooler blood will be circulated back through the body. She also perspires. As the water is evaporated, it also takes away some of her body heat. But, with the rush of warm blood to the surface, she initially feels hot.
The success of the cooling off mechanism accounts for the chills that follow--it worked too well. Dizziness is because so much blood has been diverted for the flash, that the brain get short-changed for a moment. The perception of anxiety is due to the phenomenon of mis-interpreting heart racing from purely physical causes to anxiety.
All this is clearly associated with lower hormone levels (particularly estrodiol, estrone, and sex hormone globin binding levels). But, these are not proven to be the cause. No one knows exactly what starts a hot flash. No one knows who turns down the thermostat, in the first place.
Hot Flash Statistics
Average age of onset -- 48
How many women and when:
Up to 85% will have them
30% have them within 3 years of menopause
50% within in one year of their menopause
20% will have them 4 years after menopause
Duration:
Of a single flash -- 3.5 minutes average, with a range of 20 seconds to one hour
Of all a woman's flashes -- 2 to 3 years average
Average number of flashes per day - 3-4 on average
Where -- more than half start in the head and neck
How bad:
50% -- describe them as barely noticeable
35% -- moderate flashes with sweating
15% -- interfere with activities/seek medical help
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