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This Massachusetts startup wants to track your sweat


An old commercial for deodorant says, never let them see you sweat. NPR's Science Desk begs to differ. They've been studying sweat this summer, and Ari Daniel has the latest in sweat-sensing technology.

ARI DANIEL, BYLINE: To learn about all that our individualized sweat has to tell us, I headed over to Epicore Biosystems, a startup based in Cambridge, Mass.


DANIEL: I'm escorted into a small room where AJ Aranyosi, the 50-something chief scientific officer, is booking it on a treadmill. And he's just dripping.

AJ ARANYOSI: I've been the heaviest sweater since we founded the company.

DANIEL: Aranyosi shows me his left forearm, where he's got a hexagonal patch the size of a stout Band-Aid. His sweat wicks through narrow channels that snake across its face. The company developed the patch in partnership with Gatorade. It's a one-time use, and a two-pack retails for 25 bucks. Roozbeh Ghaffari, the CEO, says we tend to underappreciate the value of sweat.

ROOZBEH GHAFFARI: We just take it for granted, wipe it off, throw it into a laundry basket. But turns out there's this treasure chest of information that's just there. And it varies from person to person.

DANIEL: And from day to day, based on weather and workout. The patch changes color according to how much you sweat and how salty it is.

GHAFFARI: We can determine your total fluid loss, and that tells us immediately what we need to put back into your body. How do we rehydrate?

DANIEL: In other words, what optimal mix of fluid and electrolytes do you need in the moment? Aranyosi uses an app on his phone to snap a picture of the patch, which translates its orange and purple colors.

ARANYOSI: Gives me my sweat rate. So I filled almost three-quarters of a big bottle of Coke. And then my sodium loss was fairly high, meaning my sweat was pretty salty today.

DANIEL: The team sees benefits for elite athletes to avoid cramping and heatstroke. But sweat monitoring could be useful for workers in high-heat environments, too. On each of Aranyosi's biceps is another sensor currently under development. It's like the patch, but it's got a little packet of electronics that continuously monitors fluid loss and salt content. If the wearer starts to become dehydrated, the device vibrates - a signal to drink fluids quickly. Aranyosi says the device will help those working in construction, oil fields, farm fields.

ARANYOSI: Being able to tailor recommendations about how to stay hydrated is going to help improve worker safety overall, especially as summers get hotter and hotter.

DANIEL: Looking ahead, the company plans to track stress hormones and other components in sweat - a fluid, in their eyes, flowing with all sorts of health data if you're willing to soak it up.

Ari Daniel, NPR News.


Ari Daniel is a reporter for NPR's Science desk where he covers global health and development.