Gauging the Natural, and Digital, Rhythms of Life

Walking, sleeping, talking: it’s the stuff of everyday life. Add sensors that track all of it, and suddenly everyday life becomes an opportunity for knowledge.

Electronic bracelets like Nike FuelBand, Jawbone Up and Fitbit Flex tally information like the number of steps taken each day and hours of sleep. Those personal statistics, the line goes, can inspire people to move more, eat better, sleep longer.

Or at least that is the line for the generally affluent, health-conscious people who wear these things.

“There’s an element of narcissism, but also narcissism is good to the extent that it makes you healthy,” said Esther Dyson, a technology investor who wears several body sensors herself, often at the same time.

An individual’s biometric statistics â€" call them small data â€" could get a lot more intriguing and useful for everyone if they were pooled into giant vats of data from thousands or even millions of people. Researchers are starting to use body sensors, includingthe ubiquitous smartphone, to glean a deeper understanding of how behavior, environment and other factors are related to disease.

“The Big Data implications of having all this biometric data is going to be significant,” said Deborah Estrin, a professor of computer science at Cornell’s technology campus in New York City and a pioneer in using mobile phones to collect data about the physical world.

Some believe the impact of wearable technologies on medicine could be akin to the effect on other fields, like advertising.

“The idea is to take everything Google and Amazon has done for marketing purposes and try to do the same thing for health care and disease prevention,” said Dr. Jeffrey Olgin, chief of the cardiology division and co-director of the heart and vascular center at the University of California, San Francisco.

Dr. Olgin is conducting one of the most ambitious efforts yet to harness wearable sensors for medical research, the Health eHeart Study of cardiovascul! ar risk. Dr. Olgin planned to begin allowing participants in the study, which started in March, to share data from all manner of body sensors, including Fitbit activity-monitoring bracelets and home blood pressure cuffs.

The participants will also be able to install an app on their smartphones from a start-up called Ginger.io that monitors how much they walk and how far they ride their bicycles. The app also can tell researchers if participants are communicating less frequently with others, by text, phone and e-mail.

Dr. Olgin said that, for now, it was difficult to know when someone with heart failure was going to experience a setback. Doctors have a checklist of warning signs, but they have limitations. They are derived from samples of the broader population â€" groups that may be as small as a couple hundred people.

“We don’t know anything about the individual and where they are on the spectrum,” Dr. Olgin said.

A person who gains weight may simply be getting fatter, rather han being on the verge of a heart attack, he said. Someone who wakes up every four hours may do so regardless of health.

With the aid of biometric data from wearable sensors, Dr. Olgin said, “We hope to be able to do that individual-level prediction, to detect subtle differences.”

While Dr. Olgin was worried that studies might attract healthy “quantified self freaks,” as he calls them, he said most participants were 50 to 70 years old, many of them with high cholesterol, elevated blood pressure and heart disease.

One participant is Dave Dye, a retired physicist in French Camp, Calif., who for the last 15 years has had atrial fibrillation, a common abnormal heartbeat. Mr. Dye, 65, has an assortment of body sensors to keep tabs on his health, especially when he is about to go cycling. He has a case for his iPhone made by AliveCor that can perform an electrocardiogram and a Mio wristwatch that shows his heart rate.

“One of the reasons I’m interested in this is I think! there ar! e patterns you can tease out of this data that can give you more feedback on lifestyle issues, as well as diagnostic information,” said Mr. Dye.

Anmol Madan, chief executive and data scientist at Ginger.io, said gathering health data through smartphones could also help with mental health diagnoses, amounting to a “check engine light” for patients heading into crisis. Sending dozens of text messages from a phone at 3 a.m., for example, could be a sign that someone is in trouble.

Novant Health, a hospital chain in the Southeast, is conducting a test with Ginger.io to detect signs of depression in diabetes patients through smartphones. “It’s definitely an early warning system,” said Matthew Gymer, corporate director of innovation at Novant.

In some cases, digital clues seem relatively mundane. Jawbone, maker of the $130 Up bracelet, is using insights gleaned from tracking billions of steps a day and millions of hours of sleep a week to recommend slight behavior changes to its user..

Through its smartphone app, Jawbone encourages people to get up and move before noon, because people who are active before midday, on average, end up with more steps for the day, said Travis Bogard, vice president for product management and strategy at Jawbone.

Nike figured out that more people were going on runs at night after analyzing data from its Nike Plus family of sensors, which include the FuelBand bracelet, a watch with GPS tracking and a smartphone app.

As a result, its product design teams increased the amount of reflective material they put on Nike apparel, said Ricky Engelberg, director of experience for digital sport at Nike.

Even some ardent believers in wearable sensors don’t think the technology will go mainstream until it stops being so visible.

Jennifer Darmour, design director at Artefact, a product design firm in Seattle, has worked on prototypes for incorporating wearable sensors directly into apparel.

“We’re in the brickphone phase,â€!  Ms. Dar! mour said.