Tammy Koncitik’s clients are a stressed-out lot. Many are working full time, looking after growing children, and caring for elderly parents. “A lot of them are multitaskers,” says the member of the Rotary Club of Evanston, Wyo., USA, who owns a massage therapy business. But when her clients’ cell phones and beepers started intruding too frequently into time set aside for healing and relaxation, Koncitik took a stand. “I have a ‘no cell phone’ policy now,” she says.

Answering your phone during a soothing massage may not seem like a major distraction. And consulting with a client while answering e-mail and looking over a report for tomorrow’s meeting just means you’re highly productive, right? Not so. According to researchers, the toll of such multitasking on performance and productivity is rising as our increasingly fast-paced society tries to cram more and more activities into a set number of hours.

Brain freeze

Consider what happens in the brain when it tries to multitask.

“If you’re learning something like simple association – vocabulary for a French test by rote memorization – dual tasking will not hurt you much,” says Barbara Knowlton, a psychology professor at the University of California, Los Angeles. “But if you want to understand information deeply so you can apply ideas in new situations, learning under dual tasking – when you’re listening to music, or have the TV on, or you’re in a coffee house – probably is not as effective.”

Knowlton coauthored a 2006 study that examined the learning process when people either focus on one activity at a time or shift between two tasks. The report found that participants who had to multitask while learning couldn’t adapt their knowledge to new, slightly different situations. Those who focused on one task, however, “could be a little more flexible with their knowledge,” Knowlton explains. “They could use it in different ways than they originally learned it.”

So how does this apply to everyday life? Imagine an experienced club newsletter editor who needs to proofread some stories. She’ll probably be fine if she listens to music or even checks her e-mail while she’s working. But when that same Rotarian has to learn how to set up the club’s Web site, she’d better turn off the phone, music, and e-mail alerts and focus on mastering a new set of skills.

“If you’re going to have to be able think on your feet, it’s better to focus,” says Knowlton.

Time warp

Studies also show that multitasking actually saps time rather than saving it. Researchers from the University of Michigan and Federal Aviation Administration report that it takes people longer to get things done when they’re continually switching from one task to another. Their 2001 study in the Journal of Experimental Psychology: Human Perception and Performance showed that multitaskers must constantly reorient themselves to various activities, which takes extra time. The more complex the tasks, the more time is lost. The researchers say the cumulative loss can amount to as much as 40 percent of workers’ productive time.

Still, many U.S. laborers have to juggle more tasks and finish them more quickly than in the past, according to a 2004 report by the Families and Work Institute. In the study, which surveyed about 1,000 people in the U.S. workforce, 56 percent of employed adults said they had to work on too many tasks at the same time either often or very often and that interruptions during the day made it difficult to get anything done. Of the 316 people who said they were highly overworked, 52 percent said they sometimes or often made mistakes because they had too much to do.

Rest and motion 

The report recommends that employers consider how athletes are conditioned: with downtime between competition and practice. “The way our minds work, we function better with rest and recovery,” says Ellen Galinsky, the institute’s president and a coauthor of the study. “People in sports know you can’t just push, push, push.”

Those who don’t recognize their limits could be headed for a fall. “It’s not just your brain that’s affected,” says Alice Stuhlmacher, director of the industrial and organizational psychology program at Chicago’s DePaul University. “You can develop heart disease or high blood pressure. Your brain helps you interpret if something is stressful, and your body shows those symptoms.”

Stuhlmacher adds that for some it can take a crisis – be it an error at work, a health problem, or a near-miss while driving and talking on a cell phone – to recognize the hazards of multitasking. That’s what happened to Tammy Koncitik.

To run her business, she was doing everything from scheduling appointments to keeping the books to changing the sheets on the massage beds. Without an assistant, multitasking was a must. But while she was building her business, Koncitik left a case of endometriosis untreated and eventually found her condition worsening. “I got used to living with it, until the pain started getting worse,” she explains.

Learning that she needed surgery “was a huge wake-up call,” Koncitik recalls. Now she realizes the world won’t end if she isn’t booking appointments, answering e-mails, and paying bills all at the same time. “There’s only so much one person can do,” she says.