Automatic Multi-loop Control of Cooling Garments

1) Physiological Measureinelits As the methods for the physiological measurements are described in detail elsewhere (1) only a brief summary is given here. Skin temperatures were sensed with thermocouples at ten sites. Mean skin temperature was then calculated with weighting coefficients according to the HardyDuBois-formula (2). In the case of the multi-loop experiments a local mean skin temperature of each cooling conipartxnent was calculated as the average of the local skin temperatures. Rectal temperature was measured 10 cm behind the anal sphincter (thermocouple; Ellab, Denmark). An open mask system was used to determine the standardized oxygen consumption and carbon dioxide production and finally the metabolic rate (STPD: standard iemperature pressure and ~Jry). Exercise was performed on an electrically braked cycle-ergometer. Metabolic heat production (MHP) was calculated as the difference between metabolic rate and exercise rate. With scaled turn-switches the subjects could indicate their thermal sensation and their thermal comfort independently for each cooling compartment. Heart rate was measured optically with an earclip registering the light transinission fluctuations due to the pulsatile nature of blood flow.