Sweat Signals: Wearable Microfluidics Reveal Real-Time Muscle Fatigue

A study in Science Translational Medicine introduces a skin-interfaced microfluidic wearable that dynamically monitors sweat biochemistry during exercise, offering a noninvasive alternative to blood testing. The device integrates a colorimetric timer and sensors for pH and lactate concentration, enabling real-time tracking of physiological changes over active muscle regions. Results showed that sweat pH decreases with exercise intensity and correlates negatively with blood lactate levels—a known biomarker of muscle fatigue. Crucially, this correlation was absent in non-working muscle areas and in physically fit individuals, suggesting potential applications in fitness assessment, endurance monitoring, and personalized training. This platform paves the way for sweat-based diagnostics in athletic and clinical settings.