Many people still believe that they will catch a cold if they go out in the cold without warm clothing or when they have wet hair or if they go out from a warm room into cold air or if they place themselves in front of a fan while sweating, particularly after exercise.
Colds, bronchitis and pneumonia are contagious diseases caused by infection, usually starting off as viral diseases which may become complicated by a secondary bacterial infection. You cannot pick up infections from cold weather or rain.
You will get germs from people who sneeze or cough in your face or transmit germs with their hands to objects that you will then go on to touch, hence the importance of hand washing. Research clearly shows that the easiest way to catch a cold is from someone who has a cold, sneezes into his or her hands, and then shakes yours. It is also easy to get a cold when a person blows his or her nose or coughs into a handkerchief and gets some of the germs on his hands, then touches something that you will then go on to touch, such as a door knob, even hours later. If you then put your hand in your nose or mouth, you will have successfully helped the virus to gain direct access to its preferred site – the mouth and nose. The only way that you can get a cold is for someone to give the virus to you directly (through coughing or sneezing) or by putting the germ onto something else that you touch. This also includes tears that also carry viruses.
The real question about colds is whether chilling the body hinders or suppresses the immune system to the point where viruses find it easier to invade and infect. That question has been answered many times. Chilling does not hinder immunity as long as you aren’t so cold that your body defences are totally destroyed, in which case death is likelier than a simple cold.
In 1958, Dowling and colleagues conducted a study that was published in the American Journal of Hygiene – Transmission Of The Common Cold To Volunteers Under Controlled Conditions. More than 400 volunteers were exposed to viruses that cause colds. Some were exposed to very cold temperatures while wearing heavy coats, some to 60 degree temperatures while wearing underwear, and some to a very warm 80 degrees.
The study clearly showed that all groups had the same rates of infection. This proved that the crucial factor that determines whether you get a cold is actually being exposed to the virus that causes the cold.
In 1968, Douglas and colleagues published a paper entitled Exposure To Cold Environment And Rhinovirus And Susceptibility To The Common Cold, in the New England Journal of Medicine. Inmates at a Texas prison had the cold virus placed directly into their noses and at varying times after this exposure, they were exposed to extreme temperatures, with varying amounts of clothing. Being cold or warm, being dressed or undressed, and having wet hair or dry hair had no effect whatsoever on their infection rates.
The very young and the very old are at higher risk for upper respiratory tract infections and their complications. Young children may get eight to 12 colds every year due to their immature and naïve immune system. Smaller nasal and sinus passages also make younger children more vulnerable.
Upper respiratory infection rates gradually diminish as children grow, until at school age their rate of such infections is about the same as adults.
Children who attend day care have an increased risk of colds. However, they then have lower cold rates in their first years of regular school. There is also some evidence to suggest that frequent colds in young children may help protect against future allergies and asthma.
The elderly have diminished cough and gag reflexes, and their immune systems are often weaker and, hence, they are at greater risk for serious respiratory infections than younger adults.
Exposure to smoke (including cigarettes) and environmental pollutants all increase the risk of respiratory infections in children. Specific medical conditions may naturally make colds worse, particularly those where the immune system is directly involved, such as AIDS and cancers (and treatment thereof). Stress also increases one’s susceptibility to colds and can then also make symptoms worse.
Colds are commoner in winter not due to cold or wind but due to the fact that people spend more time indoors, with closed windows and doors, enhancing and encouraging viral cross contamination from person to person. Hence, travelling in buses and planes also increases this risk.
If you do not want to get a cold, stay away from people and from crowds in general. You can get a cold from anything touched by a person who has a cold, including a pen or pencil, telephone, cutlery etc. Hand shaking may also result in a cold, and it is thus always a good idea to wash your hands before putting them anywhere near your mouth or nose or eyes.