Woman Gives Surprise Insight Into Hot Flashes
08 Oct
2004
Report finds her blood pressure dropped steeply
A purely chance combination of events may have provided
researchers with new insight into a stubbornly persistent
women's health issue: the hot flash.
A hypertensive woman participating in a study about sleep,
stress, and blood pressure happened to have a hot flash.
Equipment set up to monitor the woman's blood pressure
recorded a dramatic decline in that pressure.
"She had the blood pressure device on that allowed us to
measure blood pressure, and she spontaneously noted that she
was developing a hot flash. This does let us document for
the first time the profound change in blood pressure and the
heart rate response as an effort to counteract the drop in
blood pressure," said Dr. Joel E. Dimsdale, professor of
psychiatry at the University of California, San Diego. "We
took advantage of serendipitous events. We were studying
this woman for other reasons."
"You would expect blood pressure to drop. The thing that was
striking to us was the magnitude of the drop," continued
Dimsdale, who is co-author of a letter documenting the
findings in the Oct. 7 issue of the New England Journal of
Medicine. "We were stunned by the magnitude of the
response."
Hot flashes are a commonplace event in women entering and
well into menopause; according to some estimates, two in
three women will experience them. Still, scientists still do
not have a clear understanding of the mechanism behind them.
Certainly, hot flashes are associated with fluctuations in
heart rate and flushing. "What we haven't known has been the
moment-to-moment observations of blood pressure," Dimsdale
said.
The reason for this is that only recently has the equipment
been available to noninvasively measure blood pressure
heartbeat to heartbeat. "If you were to have a hot flash and
wanted to know your blood pressure, by the time you could go
grab a blood pressure cuff and pump it up, it would all be
past," Dimsdale explained.
Serendipity conspired to change that.
The 46-year-old, unidentified woman participating in an
unrelated study happened to report a hot flash while hooked
up to a device that provided continuous, beat-to-beat blood
pressure recording. During the flash, her blood pressure
dropped substantially, by 40 millimeters of mercury,
followed by a rise in heart rate.
Heartbeat typically accelerates after a drop in blood
pressure as a way to compensate. Researchers had speculated
that this "baroreflex," which essentially works to stabilize
blood pressure, was linked to certain changes that took
place during a hot flash.
When researchers asked other women in the study to inhale
amyl nitrate, which makes blood vessels wider, a number of
menopausal women reported having hot flashes.
The findings raise the question of whether women who have
impaired baroreflex functioning, such as women with
autonomic neuropathy, might also suffer worse menopausal
symptoms. Autonomic neuropathy occurs when the nerves that
regulate the part of the nervous system that is not under
your conscious control are damaged.
So far, however, the researchers have information on only
one woman -- and a woman with high blood pressure at that.
There is no way to generalize to other women.
"One would expect that if blood pressure drops, that the
heart would compensate. But why does this happen in women
going through menopausal treatment?" asked Dr. Steven
Goldstein, professor of obstetrics and gynecology at New
York University School of Medicine. "There's no clue to that
in this report."
More information
For more on menopause, visit the North American Menopause
Society.
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