As another sweltering Texas summer approaches, the danger of dehydration is ever-present. While this condition can range from a minor inconvenience to a life-threatening emergency, tracking hydration levels is a challenge.
A team of researchers at The University of Texas at Austin has developed a breakthrough solution: a non-invasive wearable sensor that continuously measures an individual's hydration status in real time. This device could assist athletes in maintaining proper hydration during intense activities, help firefighters stay hydrated while battling fires, or simply remind office workers when it’s time to refill their water bottles.
"Dehydration poses a silent danger affecting millions daily," notes Nanshu Lu, professor at the Cockrell School of Engineering's Department of Aerospace Engineering and Engineering Mechanics, who led the study published in the Proceedings of the National Academy of Sciences.
Proceedings of the National Academy of Sciences"Our wearable sensor offers an easy and effective method for real-time hydration monitoring, enabling individuals to take proactive measures toward maintaining health and peak performance."
The device employs bioimpedance technology, which gauges electrical signal transmission through the body. Through strategically positioned electrodes, it sends a small, harmless electric current across the arm.
The flow of electricity varies depending on tissue moisture levels. Hydrated tissues allow easier passage for the current due to water’s conductive properties, while dehydrated tissues resist the flow.
Data collected by the sensor is wirelessly transmitted to a smartphone app, allowing users to observe their hydration status in real time.
The researchers conducted several tests to validate the device's efficacy, including a diuretic-induced dehydration study and a 24-hour free-living trial. In the controlled study with diuretics, participants experienced fluid loss while both the wearable sensor and urine sample measurements tracked their hydration levels. Results indicated a strong correlation between changes in arm bioimpedance and weight loss resulting from water depletion.
"Our experiments confirm that arm bioimpedance not only detects hydration variations but also aligns closely with full-body hydration metrics," said Matija Jankovic, co-author of the study and postdoctoral researcher at Lu's lab. "This suggests that our sensor serves as a dependable indicator for monitoring hydration levels even during daily activities such as walking, working, or exercising."
Traditional hydration assessment methods like urine tests or blood analysis are often invasive, time-consuming, and impractical for continuous monitoring. Commercial devices typically require cumbersome equipment and stationary setups, limiting day-to-day use.
Proper hydration is crucial to human health, as it supports organ function, regulates body temperature, and facilitates vital physiological processes.
Dehydration—a condition arising from insufficient bodily fluids—remains a common yet neglected issue. Even mild dehydration can impact cognitive function, physical performance, and thermoregulation, while severe dehydration may lead to serious risks such as kidney stones, cardiovascular problems, and heatstroke.
The device could have implications beyond extreme environments since continuous hydration monitoring might also aid in diagnosing and managing health conditions like kidney disease, cardiovascular issues, and chronic dehydration. "Ultimately, this innovation aims to support our Longhorn student athletes in competing safely on hot days," Lu added.
Although current sensor models track relative changes in hydration levels, future research will set baseline data for absolute measurements by collecting bioimpedance readings from a diverse population.
The researchers also intend to develop new designs focusing on comfort and performance enhancements, such as breathable e-tattoos or moisture-wicking wearables. Expanding trials to larger groups and exploring the device's application on other body segments like the forearm or thigh are additional goals.
"We've only just begun," Lu said. "Our aim is to make hydration monitoring easily accessible for everyone."