When John Osborn’s treadmill desk arrived in his corner office last August, the New York CEO of advertising firm BBDO spent nearly 80% of the day working while walking. But soon colleagues began pointing out rampant misspellings in his emails. “You quickly realize how difficult it is to type anything longer than a sentence,” he says. And while he had hoped to drop some weight, he found that after a few weeks, his appetite increased. “The big joke around here was I got the treadmill desk and I put on 6 pounds,” Osborn says.