Gravimetric measurement includes collecting sweat secretion on standardized filter. Prior to any measurements, the subject will be asked to sit in a climate-controlled room for 15 min to allow for acclimatization. Filter paper is first weighed on a high-precision laboratory scale. The filter papers are then placed in the subject's palms for 5 minutes, and weighed again. This technique has already been used in other studies of hyperhidrosis [5]. The difference in the weight (g) will allow calculation of sweat secretion in grams per 5 minutes.