Correspondence

Hot-Flash Hypotension

N Engl J Med 2004; 351:1577-1579October 7, 2004

Article

To the Editor:

The hot flash is one of the most commonly encountered symptoms of menopause, yet there is little understanding of its underlying physiology. With its unpredictable onset and evanescent nature, this troubling symptom has been difficult to study. The peripheral vasodilatation and rise in skin temperature are readily apparent, but what else happens during a hot flash?

A 46-year-old, hypertensive, black woman was participating in a study in which we were examining the relationship of sleep and stress to hypertension. On enrolling in the study, she reported having menopausal symptoms, including hot flashes.

A continuous beat-to-beat blood-pressure recording (Colin Pilot, Colin Medical Instruments) was obtained as part of the larger study protocol, and the observations during a hot flash were strictly serendipitous. The patient reported experiencing a hot flash during a resting baseline period of the testing. Simultaneously, the technician observed that the patient was sweating profusely and that her blood pressure had dropped by more than 40 mm Hg. Figure 1Figure 1Blood Pressure and Heart Rate Measured during a Hot Flash. shows the 3-minute recording of the patient's heart rate and systolic blood pressure, smoothed to 10-second intervals, around the time of the hot flash and during the second resting interval, without a hot flash, approximately 30 minutes later. Figure 2Figure 2Blood Pressure and Heart Rate in Four Women without Hot Flashes. shows the mean (±SE) resting systolic blood pressure and heart rate in four other black women with blood pressure levels, body-mass index, and age that were similar to those of the first woman, who were tested under the same protocol. None of these women reported hot flashes during testing.

As Figure 1 shows, there was a substantial decrease in blood pressure during the hot flash. This decrease was quickly followed by a rise in the heart rate. The acute drop in blood pressure accompanied by the equally brisk increase in the heart rate is typical of the baroreflex response to an acute hypotensive episode. It has been speculated, but not documented, that the thermogenic changes occurring during a menopausal hot flash are baroreflex-related.1,2 When we tested baroreflex tone by having the participants inhale the vasodilator amyl nitrite, a number of menopausal women spontaneously reported that they felt as though the medication was giving them a hot flash. These observations add new depth to our understanding of “vasomotor instability,” long reported to be a hallmark of menopausal symptoms. Given the corrective role of the baroreflex response in this setting, one wonders whether menopausal symptoms are more severe in women whose baroreflex functioning is impaired (e.g., women with autonomic neuropathy).

Richard Nelesen, Ph.D.
Pattie Krohn, B.A.
Joel E. Dimsdale, M.D.
University of California, San Diego, La Jolla, CA 92093
jdimsdale@ucsd.edu

2 References

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   Charkoudian N. Skin blood flow in adult human thermoregulation: how it works, when it does not, and why. Mayo Clin Proc 2003;78:603-612
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   Freedman RR. Biochemical, metabolic, and vascular mechanisms in menopausal hot flashes. Fertil Steril 1998;70:332-337
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Citing Articles (8)

Citing Articles

1. 1

   Pauliina Tuomikoski, Olavi Ylikorkala, Tomi S. Mikkola. (2011) Menopausal hot flushes and vascular health. Annals of Medicine 43:4, 283-291
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2. 2

   Emily D. Szmuilowicz, JoAnn E. Manson. (2011) Menopausal vasomotor symptoms and cardiovascular disease. Menopause 18:4, 345-347
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3. 3

   Pauliina Tuomikoski, Petri Haapalahti, Olavi Ylikorkala, Tomi S. Mikkola. (2010) Vasomotor hot flushes and 24-hour ambulatory blood pressure in recently post-menopausal women. Annals of Medicine 42:3, 216-222
   CrossRef

4. 4

   Jonathan N. Johnson, Kenneth J. Mack, Nancy L. Kuntz, Chad K. Brands, Coburn J. Porter, Philip R. Fischer. (2010) Postural Orthostatic Tachycardia Syndrome: A Clinical Review. Pediatric Neurology 42:2, 77-85
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5. 5

   Lisa Gallicchio, Susan R. Miller, Howard Zacur, Jodi A. Flaws. (2010) Hot flashes and blood pressure in midlife women. Maturitas 65:1, 69-74
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6. 6

   Robert D. Hoeldtke, Kimberly D. Bryner, Hugh C. Palmer, Lori Eddy, Linda Stark, Gerald Hobbs. (2009) Effect of octreotide on postmenopausal hot flushes. Clinical Autonomic Research 19:1, 69-72
   CrossRef

7. 7

   David A. Low, Scott L. Davis, David M. Keller, Manabu Shibasaki, Craig G. Crandall. (2008) Cutaneous and hemodynamic responses during hot flashes in symptomatic postmenopausal women. Menopause 15:2, 290-295
   CrossRef

8. 8

   Linda M. Gerber, Lynnette Leidy Sievert, Katherine Warren, Thomas G. Pickering, Joseph E. Schwartz. (2007) Hot flashes are associated with increased ambulatory systolic blood pressure. Menopause 14:2, 308-315
   CrossRef