Drivers from American School Bus Company in Frankfort climb stairs at Lincoln Mall in Matteson during a morning walk in early February. (Zbigniew Bzdak, Chicago Tribune)

On a warm, sunny Thursday morning in Frankfort, school bus drivers and monitors are chatting in their cafeteria-style lounge when Madonna Mikaitis enters the room to make an announcement.

"Who's walking today?" Mikaitis booms. "Let's go!"

With that, about 15 employees of American School Bus Co. pile into one of their buses and head to Lincoln Mall in nearby Matteson for the group's morning walk through the shopping center's hallways. En route, the drivers pass around a sign-in sheet with the header "Live Well — Live Long!"

Regular exercise is part of an overall wellness initiative by American's parent company, Cook-Illinois Corporation in Oak Forest. The company aims to help its 2,700 employees in 19 subsidiaries throughout the suburbs establish fitness routines and encourage healthier habits for fellow staff members. In Frankfort, Mikaitis worked with her manager and a co-worker to start a walking club in September, something people could do for free during the midday lull.

The group goes to a nearby park in warm weather and walks laps. On cooler days, they become "mall walkers."

"They look forward to it," said Mikaitis of Monee. "I think they like the break, to leave the terminal and get some fresh air, or go see what's on sale at the mall. They like to window shop."

About one-third of the country's adults are obese, according to the Centers for Disease Control and Prevention. A 2009 study in the American Journal of Preventive Medicine said one factor influencing obesity rates is that workplaces are often inactive settings where energy-dense foods — small portion size, high calories — prevail.

A typical day for a school bus driver can be a sedentary one. Many drivers in Frankfort, for instance, do routes in the morning and afternoon, but would often sit around the terminal in the interim and get little exercise.

For Mikaitis, who has been driving since November 2008, sitting on the bus, then eating too much unhealthy food at the terminal led to her being 60 pounds overweight, she said.

"I got short of breath when I walked too far," Mikaitis said. "Bending down to strap in wheelchairs for special needs kids used to be a little difficult."

Being overweight or obese increases the risk for other medical conditions, according to the CDC, such as coronary heart disease, Type 2 diabetes, high blood pressure and stroke. Little information exists to conclude that poor health makes for a riskier driver. Nevertheless, the Illinois Secretary of State requires school bus drivers to pass an annual physical certifying that they are clear of drugs and alcohol and do not suffer from high blood pressure, heart disease, diabetes or other conditions that could prevent them from safely operating a bus.

"The fact that we don't have the evidence doesn't mean that it isn't a real concern," said Gerald P. Krueger, president of Krueger Ergonomics Consultants in Alexandria, Va. "We're trying to encourage all drivers in a safety-related business that they get healthy for their own sake but (also) because you never know when one of those health conditions is going to compromise your level of alertness or your ability to respond when a crash-likely circumstance presents itself."

Additionally, in 2008, the CDC estimated that medical expenses for obese employees are 42 percent higher than those for workers of healthy weights. Medical problems from being obese can mean more sick days, medical leaves of absence and workers compensation claims.

"Companies spend a lot of money training drivers. You want to keep them," said Norm Littler, director of the Bus Industry Safety Council with the American Bus Association in Washington. "You don't want a driver coming and saying, 'I can't drive anymore because I can't control my blood pressure,' or, 'My eyesight is going because of my diabetes.'"

Almost 60 employees resigned from Cook-Illinois in 2011 for medical reasons, such as diabetes, heart disease and stroke, said human resources manager Steve Miller. In comparison, the company lost 40 drivers for medical reasons in 2010. Not all of those conditions arose because of weight problems, Miller said, but company officials recognized that obesity was something they could prevent.

In early 2011, company officials formed a wellness committee to find ways to help employees improve their fitness. One of their first moves was arranging exams and blood tests through United Healthcare.

What they learned was eye-opening, Miller said.

Of the employees who participated, 22.6 percent tested for high blood pressure and an additional 44 percent had elevated blood pressure, or prehypertension. Nearly 12 percent tested in the diabetes range for blood sugar and another 31 percent were considered prediabetic, Miller said.

Armed with that data, company officials reached out to their subsidiaries. Rather than enact a blanket policy for all its employees, Cook-Illinois officials let each group designate a "wellness captain" like Mikaitis who could create a system that worked best for their co-workers.