In a new paper published in Nature, researchers describe a novel sweat monitor embedded on a translucent bracelet. The monitor consists of a sensor array and a flexible circuit board that measures the concentration of various chemicals in sweat, as well as a Bluetooth transmitter that beams the data to a phone. Study subjects wore it on their wrist or head, and scientists analyzed data during exercise sessions.
The researchers measured four chemicals—sodium, potassium, glucose, and lactate—with the proof-of-concept device, according to an article posted on the Stat website. The Nature article showed that the researchers could detect dehydration in runners based on the concentration of sodium in their sweat.
Lead author Dr. Ali Javey of the University of California at Berkeley, said that sweat contains “a whole library” of chemicals—such as electrolytes, proteins, and heavy metals—that could present many opportunities for future studies. He said that his group is studying how a variety of diseases could be detected from sweat.
Sweat analysis is currently used to diagnose cystic fibrosis and to test for the use of illicit drugs. But the science of using sweat to more generally track a person’s health is far from fully developed, the authors concede.
In an accompanying editorial, Dr. Jason Heikenfeld, chief science officer of Eccrine Systems, which is working to develop similar wearables, described other potential applications. Sweat, he wrote, could help inform drug dosing by measuring how quickly patients metabolize drugs, or could reveal a person’s stress levels by monitoring their cortisol.
Much more research needs to be done on what sweat composition actually tells us about disease, Javey said. Nevertheless, interest in these devices is growing, with companies such as Kenzen and Eccrine Systems developing sweat-detecting wearables.