Pathophysiology on Hot Flashes in Women with Ovarian Failure Evaluated by Accelerated Plethysmography and Thermography at Rest in Response to Cold-Water Challenge Test

Hot flashes (HFs), one of the principal manifestations of climacteric disorders, are considered to represent a state in which blood vessels dilate and blood flow increases, but many aspects of the pathophysiology of its onset are still discussed. We measured serum lipid (triglyceride, total cholesterol, HDL-cholesterol) and estradiol (E2) in a young woman group, an elderly woman of HF (-) and HF (+) group. We also measured peripheral circulation values with an accelerated plethysmograph (APG) and body surface temperature values by thermography in 10 subjects in each group. Baseline values at rest and values after the cold-water challenge test were measured, and the differences between them were determined. The frequency of HFs was higher in the group with low E2 values. Age differences in serum lipids were observed, but there were no differences according to HF. Peripheral circulation decreased with age, and it was even lower in the HF (+) group. Baseline body surface temperatures, both facial and bilateral palmar, were highest in the HF (+) group. The APG index, X, of the cold-water challenge test decreased in the young woman group and became more rapid with recovery, and both the percentage decrease and the recovery rate were lowest in the HF (+) group. The pathophysiology of the onset of HF appears to be attributable to a functional regulatory disturbance, including arteriosclerotic changes associated with aging and a cardiogenic response due to E2 depletion, as well as to an increase in blood flow due to the pooling or hunting phenomenon based on instability of the regulation of local circulation