Attention all shoppers: taking the stairs protects your heart. That's the message researchers tried at a suburban shopping mall by putting up colorful signs along the steps of a staircase, and it worked. Over six weeks, use of the stairway next to an escalator more than doubled.

Normally, about 4 percent of people at the mall take the stairs but after adding the signs, that went up to nearly 10 percent. The findings were recently published in the American Journal of Health Promotion.

"A certain segment of the population clearly responds to these messages," said Frank Eves, one of the study's authors, and a senior lecturer in applied psychology at the University of Birmingham.

Eves and colleagues counted the number of people at a mall who climbed the 15 steps before the signs went up and after they were posted. They counted more than 82,000 shoppers at the mall in Coventry in western England,

"If we can persuade more people to take the stairs, then we might really have something in the war against obesity," he said.

With fewer daily opportunities for physical activity in modern society, public health officials are increasingly focusing on stairs at schools, workplaces, and even the mall. Past studies have also shown that the decision to take stairs can be manipulated relatively easily with a few signs.

Eves and his co-author, Oliver Webb of Loughborough University, also found more people walked down the stairs at the mall, even though they couldn't see the signs. The 25 percent increase suggested people had remembered the messages from going upstairs earlier, and consciously decided to take the stairs on the way down, Eves said.

Still, experts think that to change behavior long term, the signs need to be seen regularly. At the U.S. Centers for Disease Prevention and Control in Atlanta, physical activity experts tested that in a 2002 campaign to boost internal stair use.

By tacking up signs promoting stair use and transforming their ugly, concrete stairs into a carpeted, bright stairwell with artwork and piped-in music, CDC officials have bumped up stair use by nearly 20 percent.

"The cultural norm in the building has clearly changed," said Dr. Michael Pratt, director of the World Health Organization's Collaborating Center for Physical Activity and Health Promotion at the CDC.

"We're a pretty good example of the fact that knowledge alone doesn't lead people to take the stairs," Pratt said. "Once the stairs were made more attractive and we added incentives, numbers went up quite a bit."

Experts emphasize that just climbing one flight of stairs at a shopping mall is not going to improve your health. But they hope the signs may inspire some people to regularly forgo escalators in the future.

"Unless you're climbing six or seven flights of stairs a day, it's probably not a substitute for daily exercise, but every little bit helps," said Tim Armstrong, a physical activity expert at the WHO.

Eves and Webb estimated that climbing stairs for seven minutes every day could reduce your risk of developing heart disease by about 60 percent.

In a previous study in Glasgow, Eves found that overweight people responded better to the signs than normal-weight people. Overweight people are also the ones who benefit the most from stair climbing. Since the activity involves raising your own weight against gravity, the more you weigh, the more you burn.

"An overweight person might not want to do aerobics or go swimming, but stair climbing is very doable," Pratt said. "You can exercise without even really thinking about it."