CEOs often pride themselves on multitasking. Unfortunately, most of them are bad at it.

At least that's according to a new Stanford University study, which found that people who consume multiple streams of media at once -- phone calls, e-mail, and Twitter, among others -- are more easily distracted and have a harder time transitioning between tasks than people who focus on one task at a time.

While the potential downsides of multitasking have been known for years, many CEOs remain oblivious. "It still hasn't gotten into the business zeitgeist," says Stephanie Winston, an organizing professional and author of Organized for Success: Top Executives and CEOs Reveal the Organizing Principles That Helped Them Reach the Top.

While observing CEOs in preparation for her book, Winston found that many did not multitask but rather focused on a succession of tasks in order to "wring the full value from their time." But she acknowledges that with smaller companies, the CEO often plays a more hands-on role, so they might not have the option of only tackling one task at a time.

Indeed, some entrepreneurs are unabashed multitaskers. "I think multitasking is kind of a steady state for me," says Tim Westergren, founder and chief strategy officer of Pandora.

Before starting the popular Internet radio service in 2000, Westergren worked as a composer, a musician and a record producer -- a simpler time. "I didn't have a cell phone," he recalls. "I was much more [focused on] one thing at a time."

Now Westergren is constantly traveling and his iPhone is always close at hand. He says he copes by creating a distraction-free zone. "In my first two hours of the day, I try focus on things that require more sustained attention," Westergren says. "I won't turn everything off, but I won't bounce around all these different channels."

Perhaps not surprisingly, Westergren does admit to listening to music at work. "It does make me less productive," he says, "but it makes my day more enjoyable."