Is The Next Fitbit A Tattoo?

Say goodbye to those thin black bands—the next generation of fitness trackers will be barely noticeable and the most accurate they've ever been.


As with every New Year’s, fitness resolutions are sprouting, which means gym memberships, concocting the latest diets workouts to exact the sculpted body you want—and tracking it all with a fitness tracker.

Except this year’s fitness trackers aren’t the typical black band you might have become accustomed to. And why not? It’s a field that is ripe with opportunity for improvement. A wristband fitness tracker can often turn into a sweaty nuisance. It’s not completely accurate. And a belt that counts steps taken is a bulky annoyance.

So it makes sense that one of the most promising fitness trackers is a temporary skin tattoo embedded with tracking technology that is being tested by scientists. A tattoo after all solves the cumbersome, uncomfortable issues of having a device on you at all times. Researchers are developing a variety of these tiny but flexible sensors.

At the University of Illinois Urbana-Champaign Materials Research Laboratory, YuHao Liu has tested tiny sensors on human volunteers and published promising results. “For skin-mounted tattoo sensors, users would not feel them, as their thickness and weight are comparable to human skin,” Liu told The Daily Beast via email. Liu said one big advantage is that most experimental sensors are so light that volunteers do not feel them, unlike their heavier counterparts.

Liu is a leading “Lab-on-Skin” researcher, and is developing the tattoos that resemble human skin in thickness. The device’s name underscores that wearers will be carrying a mini-laboratory on their skin.

The Lab-on-Skin devices being tested can fit inside a human ear and conform closely to a wearer’s body. This can decrease the errors common in rigid electronics that cannot bend easily to follow ever-stirring muscles.

Lab-on-Skin experts Liu and Dr. Matt Pharr, of Texas A&M University, along with their colleagues, have written about the “mismatch” that’s in place when the measuring tool is brittle but the item to be measured is soft: “Managing the mechanical mismatch between hard semiconductor components and soft biological tissues represents a key challenge in the development of advanced forms of wearable electronic devices,” they write. Activity tracking works better when both the tracker and the tracked can mesh.

These approaches vastly increase comfort of the wearer,” Pharr told The Daily Beast in an email.

Liu’s temporary tattoo fits in with the next generation of fitness trackers being downsized and therefore made as accurate as possible because they take up less space. Innovations will be compacted into wearables that are vastly smaller than wristbands or pedometers.

In addition to the work of Liu and Pharr, a recent Florida A&M University College of Engineering study forecasts wearable electronics monitoring everything from heart rate to sleep quality will be razor-thin in the future. The study authors are researching human-hair-sized sensors that might even be woven into bedsheets to monitor sleep quality. “This new technology is versatile and the sensors are affordable to print,” Dr. Richard Liang, director of FAMU’s High-Performance Materials Institute, said.

Because the new sensors can be produced in printers, “It’s a big innovation that presents many possibilities down the road,” Liang said.

Manufacturers are scrambling to create the next generation of wearable fitness trackers, which earn more profit for their manufacturers every year. Yet the data collected on them is not always precise. In addition to being outright wrong about calories burned or hours of sleep, their publicized inaccuracies have even fueled lawsuits against some manufacturers. The outcome of legal cases may determine whether trackers will start to be considered “medical devices” that require FDA approval before marketing, or if they can continue to be sold based on manufacturers’ claims alone, like running shoes or tennis clothes.

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Innovations can achieve accuracy precisely because they conform to the contours of the human body. University of California Berkeley physicist Dr. Ana Claudia Arias and her team have developed a medical device the size of a Band-Aid that reads blood oxygen levels. She hopes to develop sensors that fit the insoles of shoes to warn diabetics of foot ulcers.

Meanwhile, “size-reduction experts” at Georgia Tech have packed a tiny gyroscope into a thumb ring. The ring is embedded with technology that senses thumb movements as wearers swipe their fingers with a thumb. The ring will be linked to remote devices, and by strumming their thumbs across their fingers, wearers will be able to manage a remote smartphone.

According to Cheng Zhang, one of the gyroscope developers at Georgia Tech, experimental participants tested the ring while they were sitting, and also while walking. “The (walking) result was comparable to the performance when they were sitting still,” Zhang told The Daily Beast. Importantly, the tiny gyroscope worked.

And as trackers become easier to wear, Big Data analysts hunger for the information they can generate about consumers, their preferences, and lifestyles. Insurance and pharmaceutical companies have already collected trillions of data points from millions of current fitness-tracker users who gave their consent and permission. Analyses of insurance customers’ data includes de-identification technology, so that no individual person’s heart rate—or disease—can be linked to a name. Yet technology can break down—or be hacked. But that’s not stopping the millions of people looking for the most accurate device to measure their physical fitness and attributes.