A sweat sensor device (400c) for sensing sweat on the skin (12) includes one or more sweat sensors (420) and a volume-reducing component that provides a volume-reduced pathway (480) for sweat between the one or more sweat sensors (420) and sweat glands in said skin (12) when the device (400c) is positioned on said skin (12). The volume-reducing component may include a volume -reducing material (470) and a pressure-permeated component (460), a sweat dissolvable material (490), a mechanically compliant material (570) for conforming to the skin (12), an adhesive with a vertically anisotropic sweat pathway, and microcapsules (1385) including a barrier material. The presence of a volume-reducing component reduces the sweat volume and decreases the sampling interval.
