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The unpredictability of hot flashes makes their investigation difficult. A method for continuous monitoring of subjective arousals and their objective correlates is here described and illustrated with results from one subject. Temperatures of special interest with respect to hot flashes--toe, cheek, vagina, and air--were recorded on a protable magnetic tape during routine living at home. The subject signaled the "on" and "off" of each perceived flash with a hand switch and also entered information in a notebook. She signaled 63 flashes on 5 days, during which the cheek and toe temperatures showed transient increments. Some of the flashes were labeled uncertain in the notebook. The subject also had 23 episodes of these temperature increments that she did not identify by signals as flashes. In these episodes, therefore, the mechanism of consciousness was not activated. Perceptions that coincided with transient temperature increments thus ranged as follows: subconscious, uncertain, definite but bearable, mildly distressful, and strongly distressful. Hence ambulatory monitoring can provide objective evidence of transient activation of the hypothalamic heat loss mechanism, whether perceived or not.

Body temperatures during hot flashes were measured in a menopausal woman. Internal temperatures fell after each flash; lowest: rectal, 35.6 degrees C; vaginal, 35.6 degrees C; tympanic, 35.2 degrees C. Where sweating occurred, the skin temperature fell during the flash and rose after it. Finger and toe temperatures always showed a sharp rise at the onset of a flash with a slower fall after the flash. Only the cheeks showed additional temperature rises; maximum, 0.7 degrees C. The heart accelerated 13% at the onset of the flash but slowed immediately thereafter. The flash interval was sharply demarcated by undulations in the ECG baseline. There was never any premonitory sign of the imminence of a flash. A central excitatory state seemed to build up, perhaps by the accumulation of a chemical compound, but not of heat, which was explosively dischargedmthe thermal distress was probably evoked by vascular warming in the cheeks. Dabbing the malar prominences with cold water brought prompt relief.

Newton's law of cooling was used to analyze the fall in rectal temperature post mortem in 55 cases during refrigeration in a mortuary. As with solids of low thermal conductivity, there was an initial curvilinearity to the semilog plot lasting 1 to 11 hours (related to pelvic circumference) while the proper internal temperature distribution was becoming established. Thereafter there was a linear trend representing a constant percent cooling rate r which lasted up to 24 hours for adults. This was followed by a less steep trend of cooling rate r, which was 37% less than r. This diminution in cooling rate occurred when the rectal temperature fell below 10°C and was ascribed to a reduction in the thermal diffusivity of fat. r had the highest correlation with pelvic circumference. For the nude body in still air r=15.6% to 18.4% ( T −T)/hour for children, 3.8% to 9.4% for adults. Wind increased r; the decrease due to clothing was questionable because of the paucity of cases. [ABSTRACT FROM AUTHOR]