How it helps: Sleep regulates the release of the hormone cortisol, which stimulates cells that boost the immune system, says William Ellert, M.D., chief medical officer of the Phoenix Baptist Hospital. And a well-tuned immune system is crucial for defending against the cold virus. Getting at least seven hours of shut-eye is the easiest way to steer clear of the common cold. In fact, a recent study indicates that people who fall short are nearly three times as likely to catch a cold. To make bedtime even more healthful, try using a protective pillow cover, which can help prevent a stuffy, runny nose.
Good to know: If you have trouble falling asleep, try a mind-calming exercise. For instance: “Go over everything you did during the day, but do it in reverse order,” says C. Evers Whyte, director of the Center for Health Renewal, in Stamford, Connecticut.
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How it helps: Research has shown that moderate exercise—30 to 90 minutes most days of the week—increases immune function and reduces your chances of catching a cold. Key word: moderate. Prolonged high-intensity exercise can actually make you more susceptible to sickness, according to research from Appalachian State University, in Boone, North Carolina.
Good to know: Don’t swear off workouts if you do get a simple head cold. A 2009 study at the University of Illinois found that moderate exercise can also help you recover from a cold more quickly than normal.
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A Hot—and Cold—Shower
How it helps: Temperature fluctuations jump-start your immune system, says Donielle Wilson, a naturopathic doctor in New York City. At the end of a shower, stand under the hottest stream you can take for 30 seconds, then turn the temperature to cold for 10 seconds. Repeat three times, finishing with cold.
Good to know: A steamy shower helps keep nasal passages clear and can prevent cold-causing bugs from taking up residence in your nose.
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How they help: These mollusks contain more of the mineral zinc than any other food, and zinc has been proven to support and enhance the immune system. Eating just a single oyster will give you a whopping 13 milligrams of zinc. That said, since it may be difficult to work them into your diet regularly (oyster sandwich for lunch?), look to zinc-fortified breakfast cereals, baked beans, and pumpkin seeds to help you get the recommended eight milligrams a day.
Good to know: Zinc is also effective when taken at the first signs of a cold. Oral lozenges that contain the mineral, like those made by Cold-Eeze and Zicam, have been shown to decrease the duration of colds.
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How it helps: According to a 2009 study published in the Archives of Internal Medicine, people with low levels of this vitamin, which helps to regulate the immune system, are more susceptible to catching colds. (The vitamin has also been shown to increase calcium absorption and reduce inflammation.) Multivitamins typically contain 400 international units (IU) of vitamin D, which falls within the current recommended daily allowance (RDA) of 200 to 600 IU. However, experts now suggest taking a 1,000-IU supplement on top of a multivitamin, as strong evidence indicates that the current RDA is too low.
Good to know: If you drink a lot of milk; frequently eat fatty fish, like salmon; or live in a sunny climate, you are probably getting an adequate amount, says Ellert, since these all increase your body’s stores of vitamin D.
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How it helps: Neti pots and irrigators cleanse the nasal passages with a saltwater solution. “A daily saline rinse helps sweep bacteria, viruses, and irritants from the respiratory tract,” says Ellert. With a classic neti pot, the solution is poured into one nostril, travels into the sinuses, then drains from the other nostril. Today a battery-powered irrigator can be easier and more comfortable to use (try the Waterpik Water Pulsator; $35, waterpiksinusense.com). A saline nasal spray, like Simply Saline ($6, drugstore.com), offers similar benefits.
Good to know: Clean your irrigator or neti pot with soap and water after every use. “Without good hygiene, these can be vehicles for transmitting viruses and bacteria from person to person,” says Ellert.