Tiny increases in sweat gland production translate into large changes in skin conductance. This phenomenon is being used to study the medical implication of increased sweat production.
Rosalind Picard, of MIT, has been using data from body-worn sensors to measure and correlate emotional states. Understanding emotion has significant possibilities for the treatment of autism, depression and sleep disorders. Her research using wrist-worn bands that measure skin conductance has revealed that in addition to measuring emotional states, changes in skin conductance also signal the onset of significant medical issues. For instance, skin conductance peaks just before an epileptic seizure.
The bands, commercially available to research organizations as the Empatica device, can track heart rate, temperature and activity in addition to conductance. If I understand Dr. Picard’s research correctly, measuring skin conductance has the potential for providing a host of data that can be used to understand how the body manifests both emotional and physical states.