You may be surprised to know that the common cold is responsible for around 35% to 40% of time lost from work. This condition is also responsible for 30% of missed days from school. These statistics explain that common cold is a common infectious disease. It is said that an adult can contract this condition three to four times a year, whereas in case of kids, this frequency is much higher. Kids are found to develop common cold for more than six to seven times, yearly. Apart from being common, this condition may also result in symptoms that can cause extreme discomfort. Even though the common cold is not a life-threatening condition, its symptoms can badly affect the quality of life. Common Cold Causes Contrary to popular beliefs that exposure to cold weather or going out with wet hair can cause cold, the real cause is exposure to viruses. In fact, this condition is medically referred to as viral upper respiratory tract infection. Studies show that more than 200 types of viruses are responsible for causing cold. However, rhinoviruses are found to be behind most of the adult common cold cases. Other viruses that can cause common cold include adenovirus, parainfluenza virus, coronavirus, enteroviruses, metapneumovirus and respiratory syncytial virus. There are around 110 types of rhinoviruses that get active during early fall, spring, and summer. Even the coronaviruses are found to have 30 types, but only four to five are found to cause a common cold. These viruses are active during winter and early spring. As there are many different types of viruses, it is not possible that the body develops immunity against all of them. Apart from the wide range of cold-causing viruses, new viruses develop constantly and this is another reason for the increased frequency of common cold in humans. So, attaining complete immunity against the common cold is almost impossible. It has been observed that mental stress and allergies may also contribute to contraction of the common cold. How is the Common Cold Transmitted We all know that the common cold is an infectious disease. This means that this condition can be easily spread from the affected person to others. Contraction of a common cold is often found to be caused by inhalation of the virus in the air we breathe. Even touching surfaces contaminated with these viruses can lead to a common cold. Viruses on the hands are harmless. But, when you touch your eyes, nose or mouth with contaminated hands, the viruses can infect the tissues. So, spending time with an infected person increases the chance of contracting a common cold. While, dry air and low humidity increases the chances of viral transmission, cold weather is not found to have any significant effects, as far as common cold is concerned. Smoking is another factor that increases the risk of contracting a common cold. Common Cold Symptoms Symptoms of a common cold are in fact the bodily response to the viral attack. The body activates the immune system that reacts against the action of the virus, causing the symptoms. So, those with a strong immune system respond with strong symptoms, whereas in those with weak immune systems, common cold symptoms will be insignificant. Usually, the symptoms develop after the incubation period of the virus. The incubation period is the time required by the virus to enter the human cell and reproduce, so as to cause the infection. Common cold incubation period is around eight to twelve hours. The symptoms may start shortly after the incubation period or may take another two to five days. This time period may also vary with different types of viruses. Common cold symptoms include a runny nose, nasal congestion, sneezing, cough, sore throat, watery eyes, headaches, shivering, and loss of appetite. The affected person may also develop muscle pain, fatigue and sometimes fever too. These symptoms are the body's efforts to eliminate viruses. The symptoms usually start with runny nose and sneezing and worsen during the second and third day. Gradually, these symptoms are found to subside within a week. Sometimes, a common cold may last for ten to fourteen days. In short, the common cold is considered as a self-limiting condition that subsides without any treatment. Actually, there is no cure for the common cold. You can reduce the severity of symptoms with the help of common cold remedies like steam inhalation, gargling, rest and intake of fluids. If you find no relief or if the symptoms worsen, you must seek medical attention.