However icky one may consider eccrinology, the study of sweat and other gland secretions, this liquid is a fine carrier of the same biomarkers that the medical community usually gathers from our blood, urine, and saliva. It’s also the least invasive—no needle, cup, or swab needed.
The military is looking into its uses to monitor pilots. But commercially, sweat holds enormous promise for some biotech startups that see in sweat glands the same kind of foundational technology that could spark new health-monitoring applications, much as silicon chips helped pioneer a profusion of electronic gadgetry.
The possibilities of sweat are clear: Strap a sophisticated sweat-detector patch on your arm and watch detailed data on your biochemistry gush forth on a tablet or smartphone, alerting you to a medical peril before illness or injury strike. Dehydration, stress, muscle cramping, and depression, for example, are just four of numerous maladies that reveal their presence with chemical markers in blood—and sweat.
“It opens a whole new world,” Robert Beech, chief executive officer of Eccrine Systems Inc., said of reliable biochemical data derived from sweat.
While its potential is bright, sweat’s reality is murkier. Significant scientific and engineering hurdles remain before it becomes a dependable, cost-effective, source of biodata. Sweat is time-sensitive: it begins to degrade once secreted. It also presents vastly different concentration levels for each of its chemical components—with many extremely low. This complicates biomarker sampling efforts, an endeavor that has traditionally been performed by large, expensive machines, Beech said.
Further, sweat is often a secondary indicator of actions occurring in the bloodstream, requiring some rapid detective work to follow a particular molecule or protein in sweat back to the original biochemical behavior in the body that caused it.
Keeping soldiers hydrated
The Pentagon is keenly interested in sweat, with the U.S. Air Force Research Lab awarding Cincinnati-based Eccrine a $3.96 million contract last month to further a five-year effort at making real-time “monitoring and augmentation” of ground troops and pilots a reality. The company was formed in 2013 as the result of research begun by the Air Force and a University of Cincinnati electrical engineering professor, Jason Heikenfeld—an Eccrine co-founder. The firm’s president is a former Navy SEAL, while another executive is a former Air Force pilot.
Air Force researchers want a reliable means to “to get down to that molecular level and being able to quantify what’s going on in the body, but not having to draw blood to do it,” said Joshua Hagen, a civilian chemist and engineer with the 711th Human Performance Wing at Wright-Patterson Air Force Base near Dayton, Ohio.
The lab has tested several prototypes with U.S. Special Forces—“they’re the early-adopters to tech like this,” Hagen said—but sweat monitoring has uses “across all of the DoD [Department of Defense] assets.” The goal is to make real-time analysis of sweat biomarkers a field capability. This analysis could mean preventing dehydration among infantry, an area of intense focus for all service branches, he said.
“Overexertion is a big thing in the military,” Hagen said. “Our men and women train very hard in some harsh environments. Hydration and heat stresses are huge for us right now.”
Sweat could also provide insight into the physiological performance of pilots. For example, the Defense Department gleans a surfeit of data from multibillion-dollar fighter jets such as the F-22 Raptor and F-35 Lightning II, yet it has little information on the condition of the highly stressed humans flying them.
Measuring a component of sweat called cortisol, a hormone that serves as a key stress marker, is also a focus of the Eccrine Systems research contract for the Air Force. Dehydration and cortisol detection are among the first tasks for wearable sweat monitors that U.S. war fighters will probably see in the next two to four years, Hagen said.
Wide range of molecules
Any substance in our blood that is water-soluble may be present in sweat—a wide gamut of “riders” ranging from molecules to proteins, viruses, dead viral cells, metals, and toxins, Beech said. For infants, testing chloride levels in sweat is the standard cystic fibrosis test.
“It’s a brave new frontier and I would submit to you that sweat, which is universally understudied … becomes a brand new field that’s going to be studied very hard over the next few decades,” Beech said, predicting that perspiration knowledge will advance “right up there with urology and other medical sciences.”
This type of real-time monitoring is likely to progress across a number of diverse fields, Beech estimates. Transport companies that need to demonstrate driver fitness for insurance carriers would be one potential market, he said. Industrial operations that need to ensure that workers are at peak condition might also monitor sweat closely. Sports teams would probably be interested.
Companies wanting to sell more sophisticated health-and-wellness trackers could also be a potential market for the type of technology Eccrine is developing. At the consumer level, such companies as Fitbit Inc., Jawbone Inc., and Beddit Ltd., have shown that many people are enthused about tracking their daily exertions, caloric intake, and sleep. These “wearables” are not medical grade, nor do they purport to be, but sweat detection could move their manufacturers toward more detailed data.
Health and wellness monitoring is likely to become more common, as costs drop and the capabilities rise. Oral Roberts University, a private Christian school in Tulsa, Okla., requires all freshmen to wear Fitbit activity trackers as a way to monitor their adherence to the university’s physical fitness rules. Students download the data to a Fitbit server that school officials then access, replacing the previous paper system, the Tulsa World reported. Target Corp., BP Plc, and Time Warner Inc. have also given their employees Fitbit trackers, aiming to improve health and reduce insurance expenses.
Eccrine has broad ambitions for its work on sweat, which will require plenty of that to achieve success. Says Beech: “Our intention is to be the industrial leader on the hard science aspects of how to sample sweat and use it.”