A tiny wearable patch could change how we track our health, monitoring hydration, stress, and fatigue in real time, all through your sweat.
Athletes, workers in extreme environments, and health-conscious individuals often struggle to track hydration, fatigue, and electrolyte balance in real time. The Sweat Patch prototype, developed by CEA-Leti and STMicroelectronics, addresses this gap by continuously monitoring key biochemical markers in sweat without the need for invasive tests.
The patch tracks indicators like pH, sodium, potassium, and lactate, giving real-time insights into hydration levels, physical exertion, thermal stress, and fatigue. By combining these readings with motion data from integrated MEMS sensors, it provides a comprehensive view of a person’s physiological state, helping users optimize performance, prevent dehydration, and reduce the risk of heat-related stress.
The device relies on solid-state electrochemical sensors embedded in a microfluidic network, which collects sweat through an adhesive layer. After measurement, sweat exits via a microporous evaporation layer. Compact wireless electronics transmit the data, allowing continuous monitoring even in extreme conditions.
The Sweat Patch is small and unobtrusive—3 cm in diameter and less than 1 cm thick—built on flexible substrates for comfortable wear on the arm. All components are medical-grade, biocompatible, and non-toxic, designed under CEA-Leti’s “human-use-compliant by design” framework.
At its core, the patch uses ST’s high-precision analog front-end to control and read the electrochemical sensors accurately. When paired with motion sensors, it translates raw biochemical data into actionable insights, enabling users to make informed decisions about hydration, rest, and activity in real time.
“In this novel system, all the sweat produced is efficiently collected and transported through microfluidic pathways to measurement chambers, each equipped with an electrochemical sensor, and then into the drainage system for disposal,” said Nadège Nief, Deputy Head Micro-Technologies for Biology and Healthcare Division at CEA-Leti. “While earlier generations of analysis rely on only intermittent readings, Sweat Patch ensures a continuous, stable biochemical signal that allows a dramatic improvement in analysis.”
