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Forget willpower. What you need is a digital nagging device.

Mark Hooper

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By Kara Platoni

We all know we should exercise more and eat better. Yet while the spirit may be willing, the flesh . . . well, let's say the flesh has a thing for cake and would rather watch police procedurals than take a brisk walk.

Abby King thinks we'd do better if we had a robo-reminder.

For more than 20 years, King, a professor of health research and policy and of medicine, and her lab at the Stanford Prevention Research Center have been working on automated ways to prompt people into good health habits. She started with telephone systems that could call to check in on your exercise routine. In the '90s, the lab turned its attention to portable electronics like personal digital assistants (PDAs) that could accompany you everywhere. Now, King and others in her field envision a day when everyone's cell phone will be his or her personal health concierge.

King's research shows that when people have to answer to a digital device, they shape up. In a study King's group published last February, participants who tracked their activity level on a PDA spent more than twice as much time exercising as a control group. (These weren't a bunch of technojocks—93 percent of the participants had never used a digital assistant before.) A similar study, published in June, showed that people who monitor their diets on a PDA increase their intake of vegetables and whole grains. Another recent King study compared phone calls, from either a human health counselor or an automated one, reminding people to walk briskly for 150 minutes a week, the amount recommended by the surgeon general. Although the vast majority of study participants said they'd prefer to talk to a human, in the end, it made only a slight difference in how much they walked. Most important, on average, the people who got calls from either man or machine met the goal, while members of a control group only walked an average of 118 minutes per week.

Why do these tools work? King says consistent reminders encourage people to make time for healthy habits, and nothing is more consistent than a machine. “Ninety percent of the American public knows that exercise is important and that we need to do it on a regular basis, and most Americans know that they need to do more than what they're doing,” King says. “It's not that they don't value doing it—it's the issue of having it be a priority.” Gyms and group classes can provide expertise and support, but King says many in the demographic group she studies—people over age 50—are looking for a more flexible alternative. A portable device can track the exercise you do at your own pace, and in your own space. And while it sounds like a pretty 21st-century concept to carry around a machine that reminds you to get off the couch or eat your vegetables, the underlying principle has been with us since time immemorial: it's essentially a digital nagging machine. “It's like taking your grandmother with you,” King says with a laugh.

Actually, it's probably better. King says having supportive family and friends remind you to exercise is great—when it works. But “people just aren't quite as reliable as PDAs.” And if the message isn't delivered tactfully, the human touch can be discouraging. “When the PDA reminds you, it's a neutral source—you don't end up feeling mad at the PDA or feel embarrassed because you didn't walk,” she says.

Using an electronic device throughout the day also helps people accurately track their activity. Memory is faulty, and it can be hard to gauge time when you're doing something difficult or absorbing. “Most of us think that we are much more active than we actually are,” King says. “It's very easy to over-report activity. It's not that people are trying to do it maliciously—it's just that we tend to be optimists.”

The PDAs used for King's studies collected an especially fine grain of detail, designed to give the research team insight into what motivates people to exercise, as well as what prevents them from doing so. In the walking study, participants' PDAs would beep them twice a day, asking them to answer nearly three dozen questions about their recent activities. Participants recorded where they were, how they had gotten there, what they had eaten recently, how much time they had spent walking that day, as well as what else they had been doing—say, desk work or household chores. They also answered a series of questions about mood, including their stress and fatigue levels, and noted whether they'd recently had any positive or negative social interactions, and whether those had influenced their exercise or food choices.

The PDA also asked whether any factors had made it easier or harder to exercise that day—lousy weather, maybe, or sore muscles? Good scenery, or friends coming along for the walk? The point, King says, was to capture pivot points in people's decision-making processes. While the researchers are still sifting through the data, King says a few early findings stand out: people do better when they plan their exercise into their day, and when they have a pleasant place to walk. This may seem like a no-brainer, but King points out that for older adults, safety worries about navigating traffic and avoiding crime can be an impediment to exercise.

While taking walks seems like a small change, it can have a big cumulative effect. Moderate physical activities like walking are known to promote bone density and good mental health while helping prevent diabetes, breast and colon cancer, heart disease and stroke. “We start with middle age because that's the time of life when people really do become more tuned in to the consequences of their lifestyle—people tend to start to know friends and loved ones who become ill, because that's the decade of life when heart disease and cancer and the other things that are the major killers of Americans increase,” King says. “People become more aware and more motivated, we think, to try to do something about their own health. Plus they have many, many years left, so it's wonderful to work with people when you know that if they can change this health behavior, they're going to reap the benefits of that change in the next 20 to 40 years.”

While King's PDAs and automated phone systems are still in the experimental phase, there is one health-tracking device that's already in heavy public circulation: the pedometer. The idea of counting one's steps traces its roots to manpo-kei, the Japanese protocol of walking 10,000 steps, or about five miles, every day. But the step-counting phenomenon recently has invaded American pop culture: Nike and Apple recently teamed up to design a pedometer, worn inside the shoe, that sends tracking information to your iPod, and even McDonald's has handed them out in a bid to attract the fit crowd.

Pedometers also attracted the attention of Stanford's Dena Bravata, a general internist with a master's in health policy, who is constantly on the lookout for ways to get her patients to exercise. “I noticed that pedometers were becoming an increasingly popular tool for encouraging people to walk more,” she recalls. Bravata, MS '00, wondered if the tiny devices really do get people moving. Her review of 26 studies concluded that pedometers are effective motivational tools—if people also are given a goal of how much to walk. On average, says Bravata, those people increased their activity by about 2,000 steps per day, equivalent to walking about a mile and burning 100 calories. Better yet, many of the study participants lost weight and lowered their blood pressure.

Like King, Bravata thinks tracking devices help people become aware of their own behavior patterns and remind them of unmet goals. “It's a reality check,” Bravata says. “Pedometers are really unique in that they have an extremely short feedback loop. There are not very many devices that allow people to monitor their health status and then very quickly change the outcome.” For example, if you hop on the bathroom scale in the morning and are dissastisfied with the result, no matter how much you exercise or how well you stick to your diet, the scale isn't likely to budge much by day's end. But with a pedometer, if you haven't met your step goal during the day, you can take a walk after dinner to catch up, and the pedometer will register your success instantly.

Compared to the cost of medical care, pedometers and PDAs are inexpensive. (Bravata suggests a no-frills $30 to $40 pedometer with a cover; King points out that some PDAs are now in the $100 range.) They're also relatively easy to deploy among large groups of users, making their public-health impact potentially significant. Yet as promising as these devices seem, both Bravata and King point out that research so far has skewed toward middle-aged adults. (Nintendo's new Wii Fit may provide some insight into how younger audiences respond to an electronic personal trainer.) Moreover, the researchers followed participants for relatively short time periods: King's studies tracked people for eight weeks; the average study in Bravata's analysis lasted 18 weeks. Both scholars want to know if using mobile devices can have a lasting effect. “Would the novelty wear off?” King wonders. After all, many households have a Bowflex sequestered in the basement or a spandex leotard gathering lint in a drawer.

That's why the newest push in mobile health monitoring involves a piece of equipment you probably already have: your cell phone. Researchers are drawn to cell phones because of their ubiquity and thorough integration into everyday life. Very advanced models can incorporate technologies that will help make exercise tracking even more exact science: accelerometers, which can measure movement in any direction, rather than just forward steps as a pedometer can, or cameras and GPS devices that can record where the participants are. But for Ron Gutman, the cell phone's real appeal for everyday users is much simpler: text messaging.

Gutman, MBA '05, is the CEO and co-founder of Wellsphere, a company that began when several Stanford students and researchers, inspired by the King lab's work with phones and PDAs, gathered in Gutman's living room to hash out a way to turn it into a business model. “We just thought it was a great idea,” Gutman says. The Wellsphere website, launched in 2007, allows users to set exercise goals, track their progress online, and get advice and motivational support. The site is open to the public; additionally, Stanford is a prototype for the company's BeWell program for proprietary communities, which it hopes to roll out later on other campuses and via health plans.

Gutman says the company quickly realized users wanted a portable way to log their progress. “The problem with tracking their notes in a notebook or on a computer is it's very decoupled from the activity itself,” he says. People would go to a yoga class, for example, but not remember to chronicle it via computer later that night. The company's Wellphone service, added in March, allows users to log by cell phone how much exercise they do, as well as receive text-message reminders to work out. Although Wellsphere initially was tempted to design a much more complex program, this simple reminder-and-tracking system was really all that users wanted. “The fewer the number of keystrokes, the more people used it,” Gutman says.

King agrees that the next wave of medical minders probably will be software applications that people can download onto their own mobile devices. “Certainly the ubiquity of cell phone use around the planet hints that this is the next thing to use,” she says. And while a cell phone probably will never replace your doctor as your primary health authority, in the day-to-day struggle to make healthy choices, it helps to have a fitness adviser that still makes house calls.

KARA PLATONI is a freelance journalist in Oakland.

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