The newest exercise fad can't be found in gyms, but only in offices. Greater numbers of working people are eschewing traditional office chairs for treadmills, cycling, and exercise balls while staring at spreadsheets or taking conference calls.

“There’s a glob of information that sitting is killing us,” James Levine, an endocrinologist with the Mayo Clinic, told USA Today. “You’re basically sitting yourself into a coffin.”

Studies have shown that too much sitting can increase the risk of death from cardiovascular disease or cancer, according to the Mayo Clinic. One of them found that people who sat for four hours a day in front of a TV or other screen — including a work computer — were 50 percent more likely to die from any cause and almost 125 percent more likely to experience events related to cardiovascular disease, such as chest pain, when compared to people who sat for less than two hours a day. What’s more, other research suggests that people who sit for longer periods may not benefit from any exercise they’re getting.

Now, people like Andrew Lockerbie, senior vice president of benefits at Brown & Brown, a global insurance consulting firm, are walking on treadmills while they work. He walks up to four miles on any given day, burning about 350 calories, on a treadmill desk that his company bought. By doing so, he tells USA Today, he’s able to be “productive on two fronts.”

“I’m in meetings and at my desk and on the phone all day,” he told USA Today. “It’s great to be able to have an option at my work to get some physical activity while I’m actually doing office stuff. You feel better, you get your blood moving, you think clearly.”

Lockerbie’s treadmill, and others made for working, typically move at about one to two miles per hour — just enough speed to improve metabolic rate and blood sugar levels, Levine says.

Manufacturers of treadmill desks have seen sales growths recently too. LifeSpan Fitness, a treadmill desk manufacturer based in Salt Lake City, saw sales triple in 2012. Indianapolis-based TreadDesk forecasts a 25 percent increase in sales, since major companies, such as Microsoft, Procter and Gamble, and Coca-Cola have started buying large quantities of the desks.

Other workers use large rubber exercise balls for sitting. “I’ve got nurses in my operating room who will use one of those balls instead of a chair,” Michael Maloney, a professor of orthopedics and sports medicine specialist at the University of Rochester Medical Center, told USA Today. Rather than sitting in one position all day, exercise balls force people to exercise their abdominal, back, and pelvic muscles.

For people who aren’t able to exercise while they work, doctors recommend taking short breaks to walk around or stretch, which could be just enough to wake muscles up and increase blood flow. If even that’s not possible, simply standing up could be effective too.

“Once you’re of your bottom, it’s inevitable that you start meandering around,” Levine told USA Today. “Within two minutes of standing, one [metabolic process] activates a series of metabolic processes that are beneficial. Once you sit, all of those things get switched off.”