During intense exercise—sprinting, for example—your body breaks down glucose and produces what’s called lactate. That substance can build up faster than it can be further processed. If your idea of a workout is running to the refrigerator during commercials, you probably associate the lactate buildup with a burning in your muscles.

But for well-conditioned athletes, excessive lactate means muscle fatigue and diminished performance. So athletes would like to know their actual lactate levels during training and competition. Blood tests are one way to measure lactate levels, but are not practical in the middle of a game or race. So a goal has been to find a way to measure lactate in saliva to monitor muscle endurance. Which researchers at Palo Alto Research Center, known as PARC, and the University of California, San Diego, say they’ve achieved.

Working with flexible hybrid electronics group NextFlex, the team developed a flexible, plastic mouth guard laden with sensors that can continuously monitor lactate concentrations in saliva. The mouth guard’s batteries are rechargeable wirelessly, and the device can use low-power Bluetooth to send information to smartphones, watches and other electronic devices. PARC scientists presented their work at the recent SEMI conference on electronics manufacturing in Monterey.

PARC—which is part of Xerox and best known for its pioneering work in PCs, printing and computer networking in the 1970s—has demonstrated a fully-functional prototype mouth guard. Assuming they can get additional funding, they plan to make different types of mouth guards that can be worn during high-intensity sports like football, lacrosse and boxing to measure hydration levels as well as glucose and cortisol concentrations.

With all this bodily information at hand, athletes and their coaches should be able to monitor fatigue and improve training regimens. Without breaking stride.

—Larry Greenemeier

[The above text is a transcript of this podcast.]