Picture: iSTOCK
Human DNA. Picture: iSTOCK

IT CAN be clammy and pungent, but human sweat turns out to have a positive trait — it can reveal clues about what’s going on inside you.

A team led by researchers from the University of California Berkeley said it has designed a wearable system that measures multiple chemicals in sweat and then calibrates the data according to the wearer’s body temperature. The device uses Bluetooth technology to transmit the readings to a smartphone, potentially giving doctors a real-time picture of a person’s health on the molecular level.

"The technology goes beyond state-of-the-art, with applicability both in basic studies of human physiology and in a range of clinical applications," said John Rogers, a professor of materials science and engineering at the University of Illinois at Urbana-Champaign, who was not involved in the research.

Wearable trackers, such as Fitbit, log a user’s heart rate and other vital signs. Sweat sensors aim to go deeper, analysing intricate biochemical data. But earlier models developed by various research teams measured only one compound at a time or were too big to wear. The Berkeley team, reporting Wednesday in the journal Nature, says it has developed a platform for continuous, simultaneous monitoring of several compounds over time.

Principal investigator Ali Javey and his team arranged five tiny sensors on a flexible circuit board, attached the gadget to user-friendly headbands and wristbands, and stuck them on volunteers. The highly sensitive array checked lactate and glucose, two chemicals produced when the body burns fuel; and sodium and potassium, chemicals necessary to retain water. Too much lactate can signal muscle fatigue, while low levels of electrolytes such as potassium may indicate dehydration.

"In principle, we could do studies between molecules and health conditions among much larger populations," Dr Javey said. His team plans to target the sensor for commercial and clinical applications. The project was funded by the Berkeley Sensor and Actuator Center and the National Institutes of Health.

Some experts noted that sweat-sensor technology was still in its infancy and required more research. Gaps could form between sensors and skin, and the device won’t work accurately if the user isn’t continually sweating, said Jason Heikenfeld, a professor at the University of Cincinnati and the chief science officer of Eccrine Systems, a company that is developing its own sweat-sensing product. But, he said, the Berkeley group’s apparatus was "an impressive achievement."

"We’re beginning to address the hard science of wearables," Dr Heikenfeld said. "This represents a step forward. It’s the first public preview into what is possible."

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