CONTINUOUS MONITORING OF SWEATING BY ELECTRICAL-CONDUCTIVITY MEASUREMENT

A method of continuous monitoring of sweating was developed in which s weat was detected by changes in the conductivity of perfusing water. A n ion-free solution was perfused at a constant flow rate through a cha mber attached to the skin surface. The chamber was designed so that th e electrodes were installed inside at the inlet and outlet, and a 14 m m(3) channel was constructed at the bottom to wash out sweat. The 90% response time was 0.12 s. Attaching the chamber to the palm allowed me asurements to be made with the subject seated in a comfortable environ ment. The sweat rate and heart rate were measured simultaneously with an air-ventilation chamber and a heart rate counter, respectively, wit h the subjects at rest, and under stresses such as grasping hands and doing mental arithmetic. This method yields sweat responses similar to those obtained with an air-ventilation chamber and simultaneous heart rate measurements. The main advantages of this method are faster resp onse time and smaller observation area.