Resettable Microfluidics for Broad-Range and Prolonged Sweat Rate Sensing

:wearable sweat sensors are emerging as promising platformsfor personalized and real-time tracking of evolving health andfitnessparameters. While most wearable sweat sensors focus on trackingbiomarker concentration profiles, sweat secretion rate is a key metricwith broad implications for assessing hydration, cardiac, and neuralconditions. Here we present a wearable microfluidic sensor for continuoussweat rate measurement. A discrete impedimetric sensing scheme relyingon interdigitated electrodes within a microfluidic sweat collector allows forprecise and selective sweat rate measurement across a broad physiologicalrange. Integration of a manually activated pressure pump to expel sweatfrom the device prevents sensor saturation and enables continuous sweatrate tracking over hours. By enabling broad range and prolonged sweat ratemeasurement, this platform tackles a key obstacle to realizing meaningfuland actionable sweat sensing for applications in exercise physiology and medicine.