If your medicine cabinet is full of hair serums, sprays and masques (guilty), you'll have to go on a product fast. "People always think you need dry shampoo, but really the more product you use, the dirtier your hair gets," Mika says. Instead, arm yourself with just two beauty tools: a boar bristle brush and shower caps. The boar bristle brush will give more than one with synthetic fibers to smooth the hair. And when you're in the shower, double up on shower caps to keep hair from getting frizzy in the humidity. (Since Paulina had no shower caps on hand, she skipped the showers and took baths instead.)

However, just like diets, you get cheat days. If you have extra dry hair, you can use a serum or light shine spray, but overall it's better to skip product. You can also apply a little leave-in conditioner just on the ends of hair to touch up a "stale" blowout and add polish. To keep bangs from lying flat against your forehead, Mika recommends using a light finishing spray like Schwarzkopf Professional Osis Plus Elastic Finish, $18, sprayed on a finishing brush or paddle brush to comb through your bangs and add volume.

By day three with no washes (and six bike rides wearing her helmet to and from work, a volleyball game, Nike training club, and oh -- a couple of barre classes as well) Paulina employed every woman's two-second beauty trick to feel better: red lipstick. A bright lipstick draws focus to the mouth and distracts from a lackluster hair day. "My hair is pretty low-maintenance, so the ends were still shiny and soft but my roots and bangs were starting to get greasy," Paulina says.

"By the fourth day I couldn't stand bangs in my face anymore," Paulina says. When all else fails (even that killer pink lipstick), an embellished headband covers your roots and distracts from a less-than-stellar hair day. Utilize the oil that's already in your hair to your advantage and enjoy a frizz-free, pulled back style.

After five days we threw in the towel -- no pun intended -- and Paulina was able to wash away the week's residue. Maybe we could have made the blowout last longer, if we asked Paulina to avoid all of her sweat-inducing activities, but the goal of the experiment was to find out how to make a blowout last while still going about your daily life. Otherwise, really, what's the point? To thoroughly cleanse your hair of environmental pollution, build-up and grease, use a clarifying shampoo like Elucence Volume Clarifying Shampoo, $6. "After seeing how I could make my style last I've thought about straightening my hair on a Sunday night and wearing it to work Monday and Tuesday, so I won't have to think about my hairstyle," Paulina says. "Plus, not having to think about my hair made me spend an extra minute on my makeup. I would actually take the extra time to grab the bright lipstick and an eyeliner."