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A Temporary Tattoo That Lets Athletes Know When To Take A Break

University of California-San Diego researchers have created a wearable biosensor that measures lactate levels in sweat in real time. Future iterations could transmit data to a smartphone app via Bluetooth.

What’s the Latest Development?

Joseph Wang and colleagues at the University of California-San Diego have created a biosensor that sticks onto the skin — much like a temporary tattoo — and measures the amount of lactate in the wearer’s sweat in order to determine when they are about to “hit the wall” during vigorous exercise. It works by using an enzyme to oxidize the lactate, releasing a small amount of electrical current. The more lactate present, the larger the current. A device attached to the sensor measured the current during tests, but Wang says that in the future they hope to transmit the data wirelessly using Bluetooth.

What’s the Big Idea?

Rising lactate levels are an early sign that a body’s energy stores are waning, and precede the sudden fatigue often associated with hitting the wall. Often, lactate levels are measured via blood tests. A wearable biosensor that doesn’t slide off during exercise is much more convenient, and tests showed that its readings were just as accurate as those taken by scraping sweat off test subjects and analyzing it in a lab. 

Radu Razvan /

Read it at New Scientist


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