Changes in skin blood flow and body temperatures during climacteric hot flushes

Blood velocity changes in the radial, temporal and lateral thoracic arteries have been measured quantitatively during climacteric hot flushes by means of an ultrasonic velocity meter. In the radial artery the median increase in velocity was 6 times greater than the basal velocity (range 4-10); in both the temporal and the lateral thoracic arteries the median increase was 1.5 (1.5-3). Simultaneous temperature measurements showed a fairly high increase in finger temperatures. An initial increase in temperature on the forehead was followed by a decrease. The core temperature measured on the tympanic membrane decreased. The pattern of blood velocity which increases during hot flushes, is identical to the pattern seen when someone is transferred to an uncomfortably high temperature. This similarity points to the hot flush as a time in which a heat loss occurs. As temperature measurements show no accumulation of heat prior to the flushes, it is reasonable to assume that hot flushes are the result of a central disorder of temperature regulation.