Monitoring Dynamic And Reciprocal Interacting Biosystems: Sleep And Thermoregulation

Abstract

In a group of ongoing field experiments designed to study circadian interactions between the thermoregulatory and sleep systems in normal sleep and insomnia, a completely ambulatory monitor is employed. Six temperature sites along with activity level are continuously read with readings being stored at 5-min intervals across the 24-hour day. Rectal and tympanic temperatures, as approximations of deep body and hypothalamic temperatures, respectively, along with four skin temperatures, right and left ventral upper chest and right and left ventral ankles, are used in these studies. Tympanic temperature shows a circadian variation similar to that of rectal temperature, with the coupling of the two being highest during the sleep phase (lowest activity level) of the 24-hour day. The skin temperatures from the ankles are representative of the isolated, peripheral shell temperature. They show a reciprocal circadian variation when compared to both rectal and tympanic temperatures, reinforcing the concept of a circadian, homeostatic regulation of deep body temperature through a reciprocal, homeostatic circadian variation in heat dissipation from deep body core to peripheral shell surface.