Thomas R. Frieden, New York City health commissioner, unveiled a sign that the city is providing free-of-charge to any building that says: "Burn Calories, Not Electricity -- addresses our obesity epidemic and our environmental crisis with a single call to action."

Government officials want more people to take the stairs and studies suggest that visual prompts can boost stair use by more than 50 percent.

Just two minutes of stair climbing each day burns enough calories to eliminate the 1 pound an average adult gains each year, city officials said.

Other benefits of taking the stairs include:

-- Stair climbing burns almost 700 percent the number of calories burned standing in an elevator.

-- Men who climbed at least 20 floors a week -- about 3 floors a day -- had a 20 percent lower risk of stroke or death from all causes, one study said.

-- Stair climbing has been shown to raise good cholesterol and improve cardiovascular health.