What does it take to make people more physically active? Maybe just a sign.Signs posted in buildings prompting people to take the stairs instead of the elevators proved successful in getting them to hoof it, a study finds. Signs were placed in three multistory buildings in New York: a three-story health clinic, an eight-story academic site and a 10-story affordable housing building.

The signs featured a pictogram of a man walking up stairs with text that read, "Burn calories, not electricity. Take the stairs." The submessage read, "Walking up the stairs just 2 minutes a day helps prevent weight gain. It also helps the environment."

The signs were on every floor of the health clinic and affordable housing unit and in the lobby of the academic building. A health education event also was scheduled.

Researchers tallied 18,462 trips up and down the stairs at the various sites. Right after the signs were posted, stair use increased 9.2 percent at the health clinic, 34.7 percent at the academic building and 33.6 percent at the affordable housing site.

At the health clinic and affordable housing units the signs were left in place, and increased stair use was pretty much maintained at a nine-month follow-up.

"Human-made environments in everyday life offer numerous opportunities for maintaining health, controlling weight and preventing disease," lead author Dr. Karen Lee said. "One of those health opportunities is stair climbing, a vigorous activity which can burn more calories than jogging."

The study was published online in the February issue of the American Journal of Preventive Medicine.