A wearable patch for continuous analysis of thermoregulatory sweat at rest

TLDR

The body continuously secretes sweat for thermoregulation, but low resting rates and evaporation make non‑invasive collection difficult, limiting assessment of conditions such as nerve damage, autonomic disorders, and chronic stress. This study introduces wearable patches that continuously monitor resting sweat, using microfluidics to reduce evaporation and selectively measure secretion rate. The patches feature hydrophilic fillers for rapid sweat uptake, sweat‑rate sensors, and electrochemical sensors for pH, chloride, and levodopa, enabling near‑real‑time measurement. The patches successfully captured sweat dynamics during routine activities, stress, hypoglycemia, and Parkinson’s disease, demonstrating continuous autonomous monitoring of body physiology at rest.

Abstract

Abstract The body naturally and continuously secretes sweat for thermoregulation during sedentary and routine activities at rates that can reflect underlying health conditions, including nerve damage, autonomic and metabolic disorders, and chronic stress. However, low secretion rates and evaporation pose challenges for collecting resting thermoregulatory sweat for non-invasive analysis of body physiology. Here we present wearable patches for continuous sweat monitoring at rest, using microfluidics to combat evaporation and enable selective monitoring of secretion rate. We integrate hydrophilic fillers for rapid sweat uptake into the sensing channel, reducing required sweat accumulation time towards real-time measurement. Along with sweat rate sensors, we integrate electrochemical sensors for pH, Cl − , and levodopa monitoring. We demonstrate patch functionality for dynamic sweat analysis related to routine activities, stress events, hypoglycemia-induced sweating, and Parkinson’s disease. By enabling sweat analysis compatible with sedentary, routine, and daily activities, these patches enable continuous, autonomous monitoring of body physiology at rest.