It seems we have little choice but to become masters at simultaneously juggling the demands of work, family and friends, what with our endless must-do-right-now lists. But when multitasking becomes chronic and you feel completely drained at the end of the day—every day—it may be time to stop and consider: What are the costs when you try to squeeze 25 hours of work into a 24-hour day? That’s exactly the question researchers have been exploring—particularly as the onslaught of fast-acting gizmos (cell phones, computers and PDAs) feed our multitasking culture. Do these devices really enable us to communicate, gather information and compute faster than ever?


“To do two things at once is to do neither,” wisely wrote the Roman philosopher Publilius Syrus in the first century B.C. And modern research is proving him right. In a ground-breaking study, University of Michigan psychology professor David Meyer, PhD, reveals that instead of saving time by doing several things at once, we lose time when we switch from one task to another. And this “switch-time cost” increases when we attempt more complicated or unfamiliar tasks.

“The task-supervising part of the brain, called the prefrontal cortex or PC, needs time to reorient itself every time people toggle between activities,” explains Dr. Meyer, whose work was published in the Journal of Experimental Psychology: Human Perception and Performance. That’s because the PC can do only one task at a time. Every time there’s a switch, it’s forced to reallocate brain resources. When we ask the PC to switch more often, we create more work for ourselves, taking longer than if we focus on one thing at a time.

“The brain gets tired, concentration and memory decline and performance goes down,” says Dr. Meyer. “It’s the complete opposite of what multitasking is supposed to achieve in the first place.” For example, did you know that workers are typically interrupted an average of every 11 minutes a day, and only 77% of work is resumed on the same day, says Gloria Mark, PhD, a professor of Informatics at the University of California at Irvine. Why? We return to an interrupted task after an average of two other tasks.


In an attempt to juggle her previous job as a marketing associate at a beauty product company and her personal life, New York City native Sarah Kugelman (now 44) found herself flying all over the country to attend meetings (often three in a week!), answering emails and reading trade journals while in bed and trying to date.

“Like so many other women, I felt that being super-busy meant I was being productive and heroic,” she says. “But my self-worth was so connected to how much I had on my to-do list—even when my spirit and body were suffering, I couldn’t stop the frenzied multitasking.” Eventually, Kugelman started to suffer with anxiety and heart palpitations. She also experienced chronic inner ear infections, bronchitis and even contracted the chicken pox! Her doctor told her, “If you don’t slow down you won’t live to see 40,” she says.

What are the consequences Kugelman and others pay for everyday multitasking? “These health effects stem primarily from the hormone we all know and hate: cortisol,” says Nieca Goldberg, MD, author of Dr. Nieca Goldberg’s Complete Guide to Women’s Health (Ballantine Books, 2008). Popularly known as a “stress hormone,” cortisol isn’t always a bad thing. We need some cortisol to remain alert and keep our blood pressure from dipping too low.

But when our bodies are overloaded with cortisol through sustained periods of stress and urgency (like when we juggle and switch between too many tasks at once), our bodies respond with warning symptoms. Ever notice how you “come down with a bug” when you’re stressed out? That’s because excess cortisol almost instantly decreases the number of germ-fighting white blood cells circulating in the body, explains Dr. Goldberg. Another early health consequence of multitasking: depression and anxiety. Elevated cortisol lowers production of the feel-good neurotransmitter serotonin.

In the long term, excess cortisol caused by too-much-to-do syndrome harms the heart by constricting blood vessels, which increases blood pressure and the likelihood of cholesterol plaque build-up, according to a study in Hypertension. Interestingly, that study also found that elevated cortisol is linked to low HDL (the “good” cholesterol) in women—but not in men. (Bad news, because this form of cholesterol sweeps out arterial plaques, thereby reducing the risk of heart disease, the #1 killer of women.)

Extreme multitasking also causes chronic fatigue. Excess cortisol triggered by multitasking-related stress suppresses function of the thyroid and adrenal glands, both of which play a role in maintaining high energy levels during the day and ensuring enough rest at night, explains Dr. Goldberg. When these glands aren’t working up to par thanks to too much cortisol, daytime sleepiness and other low-energy problems, like a sluggish metabolism (meaning the body can’t burn calories efficiently enough to generate enough heat) and low sex drive, can ensue.

What’s more (and we knew this one was coming), multitasking can cause weight gain. “People tend to consume more when they turn eating into a multitasked activity,” explains food psychologist Marc David, author of The Slow Down Diet (Healing Arts Press, 2005). Failing to slow down and engage in the aromas, taste and textures of food, as well as eating food in a stressed-out rush, doesn’t provide enough time for signals of satiety to get from the gut to the brain.

“Someone can eat thousands of calories in one sitting and not know it,” says David. What’s more, when the body is chronically stressed, its fight-or-flight sympathetic nervous system is activated. And because the body thinks there’s an impending emergency, it wants to conserve energy. As a result, the calories from multitasked meals aren’t burned but stored as fat—particularly around the belly, where the liver can access it quickly during that perceived upcoming emergency. The problem: That emergency never comes, leaving women with a tough-to lose jelly belly!


Forty-year-old Norma Rosenfield, head of a PR firm in Southern California, also thought that piling on the to-do’s made her “a better person somehow.” But she remembers taking her son to school one day and “feeling like a machine, just putting one foot in front of the other to get through the day.” It was then that she realized she was so mentally and physically drained of vitality that she wasn’t really present for her autistic son, her husband—or herself.

Her life-regaining strategy: “I started saying no,” says Rosenfield. It freed her time so she could connect once again with the most important people in her life. How she does it: “I start by saying something nice, like ‘I’m flattered you asked me.’ Then I say, ‘My plate is full. If I take on one more thing, I’m afraid I won’t be able to do justice to what you’re asking me.’ ” This strategy works because it lets the requester know you think their task is important, plus it brings forth empathy instead of annoyance that you turned them down, says Nancy O’Reilly, PsyD, founder of the online resource womenspeak.com.

As for Kugelman, whose experience inspired her to create a beauty product line called skyn ICELAND, which erases the effects of stress on the skin, she sets aside three hours every night to do nothing related to work. “I turn off the ‘Crackberry’ and focus on my beautiful 1-year-old daughter,” she says. This calms her mind so that when she does get back to work she’s more focused, attentive—and truly productive. Her strategy helped in other ways: She got a clean bill of health at her last physical!

Even if such a large chunk of time doesn’t suit you, says Dr. O’Reilly, spending even five minutes media-free and fully engaged in something that feels good (like cuddling with your dog or deep breathing while sitting quietly) lowers levels of stress hormones, which effectively revives the mind and body.

Multitasking may be inevitable, but it’s possible to stay sane by recognizing your limitations and multitasking smart, maintains Dr. O’Reilly. For example, limit how many times in a day you actively switch tasks (by, say, resisting the urge to check your email until you’ve completed your report), try to focus on one task at a time when you can and take mini-breaks to reduce stress. And no more of that put-on-your-make-up, talk-on-your-headset and drive-to-work insanity!

• Extreme stress
• Poor concentration and focus
• Low energy
• Decreased resistance to germs/low immunity
• Mood changes/depression
• Anxiety/irritability
• High blood pressure
• High LDL (bad) cholesterol
• Low HDL (good) cholesterol
• Suppressed thyroid function
• Weight gain, especially around the belly
• Low sex drive

About the Author: Olga Norstrom is a freelance writer based in New Jersey.