Investigation of hot flashes by ambulatory monitoring

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.