Wearable Sensors for Sweat & Hydration Monitoring

With the growing incidence of record high temperatures, extended heat waves, and extreme weather events, taking steps to minimize the risk of heat stress in workers is necessary for both safety and productivity reasons. Maintaining proper hydration is a key part of this process; just 2% dehydration is enough to cause significant short-term physical and cognitive reductions. However, both the rate and salt content of sweat can vary significantly by person, weather conditions, activity type and intensity, and other factors. Thus there is a need for personalized monitoring devices tailored to the individual and the type of activity. Here we present the Connected Hydration wearable system for monitoring fluid and sodium loss through sweat, along with fluid intake, skin temperature, and activity level. A reusable module provides control circuitry while a flexible electrofluidic sensor enables direct measurement of sweat production. Haptic motors provide real-time feedback of sweat loss, while a companion mobile app provides quantitative data and cloud synchronization on-demand. Results of field studies show that use of Connected Hydration promotes improved hydration for individual workers, and aggregated data across workers provide support for organizational changes that help reduce the risk of heat stress.