Learn the causes of a cold and how to fight back

Ever wonder about what causes the common cold? We'll go over the causes, the symptoms, and the best ways to defend yourself. Make this the season that you fight back against colds.

• The common cold could be caused by any one of 250 viruses or more that you're likely to encounter on a day-to-day basis.
• The sheer number of these contagious viruses has made it impossible for scientists to develop an effective vaccine.
• The good news? Time's on your side: the human body develops some resistance to each cold virus it encounters, which is one reason we get fewer sniffles as we age.

• Avoiding even a single nasty cold is worth far more than you'd pay in a year for hand soap, which is the only thing you'll need to slash sniffling, sneezing sick days by 45 percent.
• Along with sound sleep and good nutrition, hand washing is your best defense against cold viruses, which can survive for up to seven days on light switches, ATMs, doorknobs, and other surfaces, and for at least three hours on unwashed hands.

Some basic symptoms of a cold include: sore throat, stuffy and/or runny nose, sneezing, coughing, and even a mild fever. If you have chills, body aches, significant fatigue, or a higher fever, you may have the flu.

• Echinacea may be the top-selling herbal supplement in North America and Europe, but its cold-battling prowess remains controversial. An authoritative German review of 16 clinical trials concluded that it doesn't prevent colds (though other research says that it does).
• A worse bet: vitamin C. A definitive analysis involving over 11,700 people concluded that vitamin C has no power to prevent a cold.
• Andrographis is one remedy that can help. In one well-designed study, volunteers who took two 100-milligram tablets a day for three months had half as many colds as volunteers who got placebos.
• Probiotics are also a good choice to battle colds. These beneficial bacteria seem to increase the production of immune cells where you need them most: in the tissues lining your respiratory system. Capsules containing the bacteria Lactobacillus gasseri, Bifidobacterium longum, and B. bifidum shortened colds by an average of two days in volunteers who took them daily for three months.
• When you were growing up, you probably heard that being cold can increase your risk of catching a cold. It turns out that this might be true. The connection? Being chilly constricts blood vessels in the nose, reducing the supply of nutrients to infection-fighting white blood cells, which can allow dormant infections to roar to life.

After the inevitable snowstorms, catching a cold may be the most dreadful part of winter. Use these tips to understand colds better and take the proper precautions to guard yourself against them.