There are several theories, however, ranging from the cold affecting how viruses behave and how well our immune system copes with infections to spending more time in crowded places and getting less exposure to sunlight. Common cold and flu viruses try to gain entry into our bodies through our noses. However, our nasal lining has sophisticated defense mechanisms against these microbial intruders. Our noses constantly secret mucus.
Viruses become trapped in the sticky snot, which is perpetually moved by tiny hairs called cilia that line our nasal passages. We swallow the whole lot, and our stomach acids neutralize the microbes.
However, cold air cools the nasal passage and slows down mucus clearance. Once a virus has penetrated this defense mechanism, the immune system takes control of fighting off the intruder. Phagocytes, which are specialized immune cells, engulf and digest viruses. However, researchers have also linked cold air to a decrease in this activity.
Rhinoviruses actually prefer colder temperatures, making it difficult not to succumb to the common cold once the thermometer plummets. In one laboratory study , these viruses were more likely to commit cell suicide, or apoptosis, or to encounter enzymes that made short work of them when grown at body temperature. During winter, levels of UV radiation are much lower than in summer. This has a direct effect on how much vitamin D our bodies can make. There is evidence to suggest that vitamin D is involved in making an antimicrobial molecule that limits how well the influenza virus can replicate in laboratory studies.
Consequently, some people believe that taking vitamin D supplements during the winter months can help keep flu at bay. Indeed, a clinical trial showed that school children who took vitamin D3 daily had a lower risk of contracting influenza A. A systematic review concluded that vitamin D provided protection against acute respiratory infection. However, there have been no large-scale clinical trials to date, and discrepancies between individual studies make it difficult for scientists to draw firm conclusions.
Another factor that may contribute to cold and flu infections in the fall and winter months is that we spend more time indoors as the weather becomes less hospitable. This might lead to two effects: crowded spaces helping spread viruses-laden droplets from person to person, and central heating causing a drop in air humidity, which — as we have already seen — is linked to influenza outbreaks. However, many of us live our lives in crowded spaces all year round, and in isolation, this theory cannot explain flu rates.
Scientists continue to study seasonal patterns of respiratory infections to tease out how different factors may influence their spread.
In fact, the CDC estimate that adults have two to three colds each year. If a person does have a cold, the CDC recommend staying at home and avoiding contact with others.
These rules also apply to influenza. However, receiving a yearly flu shot is the best way of preventing flu. It can result from any one of more than different viruses. But, the rhinoviruses causes most colds.
The common cold is very easily spread to others. It's often spread through airborne droplets that are coughed or sneezed into the air by the sick person. The droplets are then inhaled by another person. Colds can also be spread when a sick person touches you or a surface like a doorknob that you then touch.
Contrary to popular belief, cold weather or being chilled doesn't cause a cold. However, more colds do occur during the cold season early fall to late winter. This is probably due to a variety of factors, including:. At the first sign of cold symptoms, you may look to stock up on any number of remedies. But what actually works? While there is no cure for the common cold, there are some proven ways to treat your symptoms. Everyone is at risk for the common cold. People are most likely to have colds during fall and winter, starting in late August or early September until March or April.
The increased incidence of colds during the cold season may be attributed to the fact that more people are indoors and close to each other. In addition, in cold, dry weather, the nasal passages become drier and more vulnerable to infection.
Children suffer more colds each year than adults, due to their immature immune systems and to the close physical contact with other children at school or day care. In fact, the average child will have between 6 to 10 colds a year. The average adult will get 2 to 4 colds a year. Colds usually start 2 to 3 days after the virus enters the body and symptoms last from several days to several weeks.
Cold symptoms may look like other medical conditions. You continue to be contagious as long as you have symptoms. Recovery from a cold usually takes 7 to 10 days. The virus responsible for the common cold can enter your body through your nose, mouth, or eyes. You might get it through direct contact. For example, someone with a cold may have the virus on their hands. If you were to shake hands with them and then touch your face, nose, or mouth afterward, you may develop a cold.
You can also get a cold from inhaling particles when a person with a cold sneezes or coughs near you. Contaminated objects and surfaces can also transmit the virus. Commonly contaminated objects include door handles, eating utensils, and shared toys.
Colds tend to come on gradually. You may begin to notice the early symptoms between one to three days after exposure to the virus. Some remedies promise to shorten the duration of a cold when taken as soon as you start noticing symptoms. Some studies suggest that taking zinc by mouth may reduce the length of a cold when taken within 24 hours after you notice symptoms.
Avoid intranasal zinc that you put up your nose. It can sometimes reduce the duration or severity of your cold. A review of clinical trials found that echinacea had only affected the duration of a cold in two out of six trials that were reviewed. It can take anywhere from 7 to 10 days to fully recover from a cold. The common cold is a contagious viral infection with an incubation period of one to three days. This means it could take up to three days for you to notice symptoms after being exposed to the virus.
Learn what you can do to prevent colds and the flu. Are you sneezing or coughing?
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