Sweanty's wearable patch for athletes tracks salt loss to help them hydrate

Wearables are coming in an increasing array of shapes, form factors and guises these days as health and fitness tracking proliferates. Here at 4YFN at the MWC tradeshow we spotted a new one: A stick-on patch for tracking athletes’ sweat to monitor salt loss and help them tailor their rehydration strategy. The Spanish startup behind these (currently) single-use wearables is called Sweanty (yes, that’s not a typo).

“We do personalized hydration plans for athletes — and these plans are based on analysis of their sweat,” said co-CEO and founder Laura Ortega Tañá, explaining the system is designed to ensure athletes re-hydrate with the correct amount of electrolytes (or isotonic drinks) after each training session. Analysis of the patch wearers’ “sweatprofile” is sent to a companion app where they access their tailored hydration plan.

This does mean the athlete needs to use a new patch every time they train. Or at least check in at key points over their training season (such as when temperatures are changing). So the cost of the tracking will certainly stack up. But pro athletes whose day job is pushing their edge are used to investing in their own performance.

Proper hydration can boost sportspeople’s performance by helping to maintain energy levels and endurance, as well as reducing the risk of cramps, per Ortega Tañá. It can also help with temperature regulation.

Sweanty’s wearables are not yet available for athletes to buy but the startup expects to launch them in Spain by the end of April. Pricing isn’t confirmed either — but she suggests it will be in the region of €120 for a box of three patches (plus three months’ access to the subscription tracking service).

The version of the wearable on show here at MWC is designed to be worn on the skin at the base of the back. Trail runners are an early focus for the startup but the patch could work for all sorts of endurance and performance sports. (Swimmers or other sports where the user is immersed in water are an exception; they will have to stick with manual methods for tracking salt loss such as weighing themselves before and after their session.)

The team is also working on an iteration of the patch that will allow the electronics components to be retained after every use, with only part of the device having to be disposed of after use.

The sweat analysis technology was developed and patented during Ortega Tañá’s PhD. She highlights a paper-based salt measurement method as a particular novelty here — with the device essentially being woken up when it comes into contact with the user’s sweat.

“The type of measurement that we’re doing is with a paper-based method. We are using a battery with two electrodes on a paper inside and when the paper is completely dry it’s not working. But when it absorbs sweat it gives power that is directly related to the amount of salts involved,” she told TechCrunch.

While athletes are a fairly narrow addressable market, Ortega Tañá suggested the technology could have wider applications, such as for fitness-conscious consumers who are active enough to want to monitor their hydration. Or for worker safety use cases, such as for people who work in very warm conditions, like construction workers or firemen, where there may be an occupational health risk. “The only requirement that we need is that they sweat,” she added.

Alerting caregivers to dehydration risk in seniors who may not be drinking enough is another potential use case she mentioned. However in that scenario she said the wearable would need to be reengineered so it could actively stimulate the wearer’s sweat reflex to be able to monitor them for salt loss.