JUDY WOODRUFF: More than 100,000 people turned out for the Consumer Electronics Show in Las Vegas this week, the annual showcase for the latest in technology, devices and high-end toys.

One of the big themes was the rising interest in health tech.

Our science correspondent, Miles O'Brien, was there to explore the potential benefits and caveats around all of this.

His report is part of our Breakthroughs series on invention and innovation.

MILES O'BRIEN: Wearing your heart on your sleeve is taking on a whole new meaning.

At the 2016 pilgrimage to Las Vegas for gadget geeks, CES, wearable health tracking devices broke into full stride, winning much more than a bit of flashy floor space and heated hype. Of course, for the growing legions of you keeping score at home on your devices, this is likely old data.

WOODY SCAL, Chief Business Officer, Fitbit: What is happening is, people are taking more responsibility for their health and fitness. They're realizing that health and fitness isn't just popping a pill. It's actually what they do that can really add up to a healthy life.

MILES O'BRIEN: Woody Scal is the chief business officer at market leader Fitbit, a $4 billion company based in San Francisco that began selling glorified pedometers in 2007.

WOODY SCAL: Seven years ago, when you talked about fitness electronics, people thought about products for triathletes. They didn't realize that these products could really address the needs of everyday people.

MILES O'BRIEN: An estimated 500 million people worldwide apparently now feel the need to copiously log their steps, leaps, strokes and spins, while recording their breathing, heart rate, blood pressure, sleep patterns and food intake, just to name a few, and then, of course, brag about it online.

LINDSEY TURRENTINE, Editor in Chief, CNET: I think humans have always been completely narcissistic. That has not changed. The technology has given us a constant virtual mirror.

MILES O'BRIEN: Lindsey Turrentine is a sporadic fitness logger and the editor in chief of CNET.com, where tracking the technology of fitness tracking has become a big, important beat.

LINDSEY TURRENTINE: We're always checking on ourselves constantly. We're checking on whether people have responded to us, and then we're also checking to see whether our bodies have responded to what we're doing. It's just another way to look at ourselves.

MILES O'BRIEN: But there is more than the psychology of self-obsession driving this sector to grow more than 200 percent a year. There's a perfect storm of technological advances as well. Sensors are rapidly shrinking in size and cost. Communications between devices has improved. And so has battery life.

And, of course, none of it could happen without the ubiquity of smartphones, our mobile switchboard for all things technological. It's a ripe convergence for the big players upstairs and the upstarts in the basement as well.

That's where we found Peter Neilson, CEO of a Denver start-up called femtoScale.

It seems like there's no limit to the amount of data people want to get. Right? Would you agree with that? What's going on?

PETER NEILSON, CEO, femtoScale: And wearables…

MILES O'BRIEN: Yes.

PETER NEILSON: … are blowing up. That's half of CES this year looks like its wearable, trying to compute everything.

MILES O'BRIEN: Neilson's company is developing a portable and eventually wearable sensor that can provide real-time readings of air quality by weighing airborne particles much too small to see. The scale is just barely visible.

I needed a jeweler's magnifying glass to see it.

PETER NEILSON: What we're really trying to do is look at, not just health care, but wellness. Can we use all this data we can get from all sorts of different things, not only to keep people healthy once they're in the hospital, but prevent them from getting sick in the first place?

MILES O'BRIEN: San Jose-based Stratio has shrunk a spectrometer down to palm size. The device shines a bright light on food and medicine to determine if they are what they purport to be.

In this demonstration, CEO Jae Hyung Lee compared counterfeit, generic and genuine Viagra to the fingerprint-like spectroscopic pattern of the real McCoy. It was instantly obvious which were the impostors.

JAE HYUNG LEE, CEO, Stratio: So far, people were just interested themselves, but now they want to know more about what they're eating. They want to know what they're buying. They want to know what's going on around them.

MILES O'BRIEN: Clearly, exercise and nutrition tracking alone are not enough to satisfy entrepreneurs or consumers in the health tracking space.

Kaustubh Kale is CEO of a Boca Raton start-up called AventuSoft. They are developing a wearable heart monitor and electrocardiogram.

KAUSTUBH KALE, CEO, AventuSoft: There's not a pushback anymore. People are already aware of Fitbit or any of the other wearables, so they're already accepting these new technologies. And now, as the technology improves, you can now push it into the medical grid domain.

MILES O'BRIEN: It's an interesting development. When you think about it, it really is no less than the democratization of medicine, isn't it?

KAUSTUBH KALE: Absolutely, yes. You're putting the power in the consumer's hands, and so they can get the data whenever they need, where they need it and with the accuracy that the doctor needs.

MILES O'BRIEN: This is where the government steps in. In early 2015, the Food and Drug Administration released a document offering guidance to industry and its own staff on regulating mobile medical applications, declaring it will only regulate apps that are medical devices and whose functionality could pose a risk to a patient's safety if the mobile app were to not function as intended.

BAKUL PATEL, Food and Drug Administration: So, the risk to patients ranges from misdiagnosis, delay in diagnosis, or when you get into the discussion of false positives and false negatives, and then you have therapeutic devices that can actually harm people.

MILES O'BRIEN: Bakul Patel is associate center director for digital health at FDA.

BAKUL PATEL: There are standards of what an EKG machine — how it should capture, what kind of wave forms, how it should be managing the signals that comes out of your body and displaying it. Those are all standards written — written for that.

If you're going to be in the market as an EKG machine, doctors better rely on them, and we ask for testing to happen, so they can actually make the same sort of diagnosis and treatment decisions.

MILES O'BRIEN: The pull of diagnostic tools out of the doctor's toolbox and into our pockets, our ears and onto our wrists is a revolution seed in part by this man, Larry Smarr.

A scientist and professor at the University of California, San Diego, he used the video wall at the school's Qualcomm Institute to illustrate the power of what's called the quantified self.

LARRY SMARR, University of California, San Diego: Big data, as it's called. And this is about me. Every one of the points on these graphs are a different blood test or a stool test in which I got a data point over a decade.

MILES O'BRIEN: Dr. Smarr began his fantastic data voyage back in 2000 with a desire to lose some weight. And so his self-prescribed testing began. He never looked back, and, before long, he spotted trouble. His self-diagnosis, Crohn's disease.

So, he brought the data to his doctor, who said:

LARRY SMARR: If you don't have symptoms, why are you here? I said, because I got data. And he said, well, that's not helpful. And so I realized, as a lifetime scientist, that the practice of medicine and the practice of science, while they overlap sometimes, are generally different.

MILES O'BRIEN: So, he fired that doctor and found another. Indeed, so many people generating so much diagnostic data may sound like a prescription for a lot of bad diagnoses, unneeded anxiety or even an epidemic of hypochondria.

LINDSEY TURRENTINE: There is such a thing as too much data if you can't deal with the data.

If you don't have software that will help you interpret the data in a smart and reliable way, or if you get overwhelmed and frustrated and you don't know how to pick it out of the big needle in a haystack sort of data pile that's building up on your phone, then it's too much data. But it's sort of up to you and how much you can handle.

MILES O'BRIEN: But a giant cloud of real-time data, really big data, aggregated, analyzed and compared with artificial intelligence, could lead to stunning breakthroughs in preventive medicine.

WOODY SCAL: Where you can figure out, how has this kind of signal been correlated with other things that have happened among a broader set of people. Someday, could you get an early alert about an impending heart event? Yes, I believe you can. I believe you will.

MILES O'BRIEN: There may be rough spots and silliness along the way, but there is no stopping the free market experiment to give us all more knowledge and more power managing our own well-being.

Miles O'Brien, the PBS NewsHour, Las Vegas.