Abstract: The disclosed invention includes sweat sensing devices configured to periodically measure sweat conductivity and galvanic skin response, devices to measure volumetric sweat flow rate, and devices that combine the three functions. The disclosure further includes methods for using a device configured to perform periodic sweat conductivity measurements, galvanic skin response measurements, and volumetric sweat rate measurements so that each sensor modality informs composite estimates of sweat onset, sweat cessation, sweat ion concentration, and sweat rate. The method uses those measurements to inform other sweat sensing device functions, such as determining the existence of a physiological condition, or performing measurements of concentrations, ratios, and trends of sweat analytes.

Abstract: The disclosed invention includes a biofluid sensing device capable of passively or actively regulating an operating temperature of one or more sensors. The device includes at least one biofluid sensor in a thermally isolated environment and at least one temperature sensor to measure sensor environment temperature. Some embodiments include at least one thermal adjustor to regulate the sensor temperature by actively regulating the sensor environment temperature in response to a signal from the temperature sensor. The invention also includes a method of regulating temperature for a biofluid sensing device having a sensor for measuring an analyte in the biofluid. The method includes measuring a biofluid sensor temperature, regulating the sensor temperature to within a selected range of the measured sensor temperature, and maintaining sensor temperature within the selected range of the measured temperature throughout device operation. In some embodiments, the measured temperature is a calibration temperature.

Abstract: The invention includes sweat sensing devices to measure volumetric sweat rate that use alternating current interrogation of electrodes, and embodiments that have a reusable component and a disposable component. The disclosure further includes a method for detecting an air bubble within a volumetric sweat rate device. The disclosure also includes methods, systems, and non-transitory computer-readable storage medium claims for using a device configured to perform periodic volumetric sweat rate measurements to inform estimates of total body water loss, to aid in the avoidance of heat stress or dehydration, and to facilitate comparison of environmental influences on heat stress or dehydration.

Abstract: The disclosed invention includes sweat sensing devices configured to periodically measure sweat conductivity and galvanic skin response, devices to measure volumetric sweat flow rate, and devices that combine the three functions. The disclosure further includes methods for using a device configured to perform periodic sweat conductivity measurements, galvanic skin response measurements, and volumetric sweat rate measurements so that each sensor modality informs composite estimates of sweat onset, sweat cessation, sweat ion concentration, and sweat rate. The method uses those measurements to inform other sweat sensing device functions, such as determining the existence of a physiological condition, or performing measurements of concentrations, ratios, and trends of sweat analytes.