The disclosed invention includes: a device and method of performing physiological sweat sensing device calibration； a device and method of indicating an individual's dehydration state； a device and method of indicating an individual's stage in their ovulation cycle； a device and method of indicating that an individual is hypokalemic or hyperkalemic； a device and method of indicating that an individual is entering a hypoglycemic state； a device and method of indicating an individual's glucose trend value； and a device and method of indicating that an individual has experienced toxic substance exposure.
