Washington ? Try to take 10,000 steps a day, Dr. Julie Gerberding advised the congressmen, a mostly graying bunch with a bit of paunch who curiously fingered the beeper-sized step-counters she’d brought them.

It doesn’t sound like much, until you consider the average person takes far less than 4,000 steps a day. Our environment — long commutes, elevators, computer-dominated jobs, remote controls that keep us on the couch — makes it too easy to be sedentary.

Now instead of lecturing Americans to exercise, health officials are trying different experiments to build fitness back into society — playing music to entice elevator users onto the stairs, starting walk-to-school programs, constructing sidewalks and handing out pedometers.

“We have to build opportunities for physical activity into everyday life,” explains Dr. William Dietz, fitness and nutrition chief at the Centers for Disease Control and Prevention, which Gerberding heads.

Specialists have long advised at least 30 minutes of moderately intense physical activity every day for overall health. Few people listen — nearly four in 10 adults report getting no exercise at all.

“We’ve engineered activity out of daily life, and we need to think about how to reverse that,” says Steven Blair of the Cooper Institute for Aerobics Research in Dallas.

It will be a massive job: Less than a third of schoolchildren get daily gym class. Suburban sprawl has their parents spending hours sitting in cars commuting to work. Roads built without sidewalks mean even families who live near schools and stores can’t walk to them. Inner cities lack safe playgrounds. Office buildings sport dank stairwells, often locked to keep out intruders, forcing people to use elevators.

That’s not even counting time spent in front of TVs or computers.

With all those obstacles, hectoring people to exercise has had little success. Dietz doesn’t even like the word exercise anymore — it suggests boring, sweaty, repetitive motion, while “physical activity” includes walking the dog or playing catch with the kids.

Hence the new focus, and millions of dollars, on researching ways to change our environment so it’s easier to get moving regularly. Some examples:

l Jazz, classical or country music fill stairways in Dietz’s building at CDC. Posting signs by the elevators that encouraged taking the newly painted and carpeted stairways only temporarily increased walking. But stair use is up 8 percent for eight months and counting since CDC added music.

l Less than a third of children who live within a mile of school walk. Programs such as Safe Routes to School and the Walking School Bus push those students to walk or bike, often in groups accompanied by an adult, while lobbying local governments for safer sidewalks and ways to ease traffic.

l Then there’s the growing advice to clip on a $20 pedometer and track how much you walk, which people usually overestimate. The hope is that the counter will remind them to seek out ways to compensate for a couch-potato environment.