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Warning to walkers: pedometers can be inaccurate
TARA PARKER-POPE, The Wall Street Journal
(Associated Press)

When it comes to improving your fitness, every step counts. But if you are using a pedometer, be warned: It may not be counting every step.

Pedometers have quickly become one of the hottest pieces of home-exercise equipment, fueled by national walking campaigns and the fast-food chain McDonald's, which is giving away pedometers in its adult Happy Meals. While pedometers were once used mainly during exercise, health experts now advise people to try to reach 10,000 steps a day and wear the devices daily to monitor all their steps, including those taken during routine activities like walking to the car.

But many of the devices, which typically cost from $5 to $55, can be woefully inaccurate. One recent University of Tennessee study comparing 13 pedometers showed big disparities between the steps pedometers counted and the steps the wearers actually took. Some devices counted every step twice, while others missed one out of every four steps.

Sometimes the problem may not be the pedometer but the pace of the person wearing it. In August, the medical journal Preventive Medicine published a study from the University of Colorado that showed pedometers are particularly inaccurate when users are walking slowly. Researchers put 257 men and women of various ages and sizes on the treadmill wearing different pedometers. On average, the pedometers missed more than one out of three steps when the pace was slower than two miles an hour. But when the pace jumped to three miles an hour, accuracy increased to 96 percent. Experts say that some pedometers just aren't as sensitive to slow movements.

This month, Consumer Reports reached a similar conclusion, showing that only three out of 12 pedometers it tested were accurate within 5 percent when used at 2.5 miles per hour.
Slow walkers, particularly those who are elderly or obese, will probably get a better result with highly sensitive pedometers, known as accelerometers or piezoelectric pedometers. In the Colorado study, highly sensitive pedometers posted 97 percent accuracy among slow walkers.

Edward Melanson, assistant professor at the University of Colorado Health Sciences Center, says many people in the center's obesity programs have complained during the years that the pedometers aren't picking up all their steps. "This shows there is some validity to that," he adds.

While one solution is to invest in a highly sensitive pedometer, even those devices can miscount. Twisting, fidgeting in a chair, bending and even driving can all trigger extra steps on some pedometers. In an Arizona State University study, a 10-mile drive on paved roads added as many as 145 steps to the count. Given that most people drive more than 30 miles a day, that translates to an extra 500 steps added to the count while you're sitting in a car. If your daily commute is bumpy, the count would go even higher.

None of this means consumers should put their pedometers on the shelf. The recent University of Tennessee study found that the Digi-Walker SW-200 and SW-701 from Japanese maker Yamax ($25-$35), the New-Lifestyles NL-2000 ($55) and the Kenz Lifecorder ($200) were all highly accurate.

Lauren Supina Farber, 38 years old, did some research to find a better pedometer after her first device seemed to be miscounting steps. She ended up with a Digi-Walker and is so convinced of the value of pedometers she has convinced several of her colleagues at the McGinn Group, a Washington, D.C., trend-analysis and communications firm, to start wearing the gadgets. Her colleagues routinely stop by and report their step counts, and have office debates about how early in the morning they should start wearing them.

"It amazes me how little walking I can get done in a day and sometimes how much walking I can get done in a day," says Ms. Supina-Farber. "When I come home at the end of the day and have only 7,500 steps, it makes me decide to walk to the store and back. It makes me much more aware."

People who use pedometers should check them for accuracy, walking 50 to 100 steps and counting as they go, then checking the pedometer to see how much it's off. In addition, a pedometer that miscounts tends to make the same mistake consistently, so it is easy to adjust your step goals, depending on whether the pedometer tends to over- or undercount.
That is what 49-year-old Chris Collins, a senior media strategist at McGinn, did after buying a $4.99 pedometer on eBay. His own test showed the device was off by about 10 percent -- he walked 50 steps and it counted 55. So now he shoots for 11,000 steps a day instead of 10,000.

Even the McDonald's "stepometer," which most experts say tends to be inaccurate, has motivated many people to try counting steps. Teresa Vollenweider, president of New-Lifestyles, a Lee's Summit, Missouri, pedometer maker, says she receives about two calls a day from people who have tried the McDonald's gadget and want to buy a better device.
Recent studies show the devices are highly motivating and can prompt significant changes in exercise habits. In one Minneapolis study of 94 patients, everyone was encouraged to exercise more, but just half the patients were given pedometers. Patients who were counting steps increased their exercise by 41 percent, or about 2,000 steps a day, by the end of the nine-week study, says Steven D. Stovitz, the Minneapolis family physician who conducted the study. Given that 2,000 steps equals about 100 calories, the extra steps could prevent more than 10 pounds of weight gain in a year.