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 A. Rogers, a professor of materials science and engineering at the University of Illinois at Urbana-Champaign, who wasn’t 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, analyzing 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 like potassium may indicate dehydration.

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