This photo provided by J. Rogers, Northwestern University, shows a soft, skin‐mounted microfluidic device for capture, collection and analysis of sweat. Time to break a sweat: Researchers are creating a skin patch that can test droplets of sweat to track health while people exercise, beaming results to their smartphones. (J. Rogers, Northwestern University via AP)

[Image above] A soft wearable microfluidic device that analyzes sweat. Credit: J. Rogers, Northwestern University via AP

The end of the year is the perfect time for a little reflection and, hopefully, relaxation.

But it’s also a time to look forward—what will the new year bring?

For many, the start of a new year comes with the hope of finally doing that one thing that you’ve been meaning to get to: the new year’s resolution.

Health-related goals dominate the most commonly made new year’s resolutions. But while 45% of Americans report making a resolution with each passing calendar, only 8% of people actually stick to their resolve.

So perhaps when it comes to staying healthy, we need a little assistance. And a new high-tech sensor might be just what you need to get your fitness program on track—or at least science the heck out of your resolution while it lasts!

Earlier this year, we saw development of some high-tech wearable sensors that can monitor sweat to provide a science-backed readout of your workout.

Sweat you say?

Sweat is more than just a stinky workout byproduct—the stuff contains electrolytes, molecules, and proteins that are excellent non-invasive biomarkers for your physiological health.

“Sweat is an interesting biofluid,” according to John A. Rogers, a researcher who is big on health-assessing wearable sensors—we’ve previously reported on LCD tattoos and biologically-powered medical devices developed in Rogers’ lab.

While the sweat sensor we reported on earlier this year was a bit clunky, however, Rogers and his team have developed a more sleek, smart, and wearable sweat sensor that just might bring on-skin fitness tracking to a gym near you.

Rogers—the Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering and Neurological Surgery at Northwestern University—and his team developed a new microfluidic wearable sensor that can measure sweat in situ to provide a real-time readout of personal health during exercise.

The soft and flexible silicone sensor design is simple—the layered device contains microfluidic channels that suck sweat into the quarter-sized sensor. Once inside, the sweat reacts in individual chambers with different chemicals, with each reaction producing a color change depending on pH, lactate, chloride, and glucose concentrations.

“We chose these four biomarkers because they provide a characteristic profile that’s relevant for health status determination,” Rogers says in a Northwestern University press release. “The device also can determine sweat rate and loss, and it can store samples for subsequent laboratory analysis, if necessary.”

And the wearable sweat sensors are smart, too—on board electronics allow wireless communication with a smartphone, which automatically launches an app when it’s in close proximity to the sweaty sensor. The app captures an image of the colorimetric changes and provides a real-time readout of the results, deciphering the wearer’s physiological health status.

See the sensor in action in the short video below from Northwestern University.

Credit: NorthwesternU; YouTube

“The sweat analysis platform we developed will allow people to monitor their health on the spot without the need for a blood sampling and with integrated electronics that do not require a battery but still enable wireless connection to a smartphone,” collaborator Yonggang Huang says in the release.

In addition to reading simple exercise health-related markers, however, the researchers say the sensors also can be tailored towards other aspects of human health, too—for example, to detect markers that indicate specific diseases.

So the sensors have wide possibilities when it comes to human health monitoring. But, the researchers note in the paper, biomarker readouts are limited to colorimetric reactions so far, although enzymatic assays are a future possibility.

The closest current possibility, however, is fitness tracking that stretches much further than existing trackers that log simple steps. And just maybe that would be enough to keep more than 8% of the American population on track with their new year’s resolutions.

The paper, published in Science Translational Medicine, is “A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat” (DOI: 10.1126/scitranslmed.aaf2593).