What Causes Colds and Flus?
The common cold and the flu are not caused by changes in temperature, but by viruses. However, the reason they seem associated with the cooler months is because different viruses are more active at certain times of the year. For instance, rhinoviruses, which have many different strains, are some of the most common causes of a cold. These microscopic germs are at their peak during the cooler months of fall and spring. By contrast, the many strains of influenza viruses peak during the winter months. Once exposed to the human body, these viruses are carried around in our respiratory systems. When they are expelled through a cough, sneeze, or nasal secretions, droplets containing the viruses contaminate the air as well as any surfaces they may land on. Once a virus infects a host, it uses the body’s cells to replicate (multiply), instigating a response from our immune system.
Our immune system is what causes the miserable symptoms we experience with a cold or flu. When an invading organism is identified by the immune system, a number of different types of cells and chemicals are released and sent to the site of the infection. They create an inflammatory response that causes our rise in temperature, the achiness and chills associated with an infection, and an increase in lung and nasal secretions. While our immune response is actively fighting the infection, these additional secretions become a risk for others, as it makes it easier for the virus to be spread when we cough or blow our noses.
Even though cold weather does not cause infections, it can contribute to our risk of getting sick. For instance, cold air, as well as dry warm air from our heaters, can cause the tissue inside our noses to become dry and cracked. This makes it easier for germs to enter into our system. Additionally, the cold weather may make the cilia (little hairs) in our noses less effective at their job of sweeping germs away. Our immune system itself may not work as well in the cold weather, either. We defend against viruses by not allowing them to replicate. However, this mechanism may be slower when the environment is colder.
Having a chronic illness also puts you at greater risk for catching a cold or the flu. For example, people who have asthma are more likely to have an asthma attack in cold weather. When the lungs become inflamed during an attack, they are more susceptible to pick up an infection. In fact, any chronic illness that makes your immune system weaker, like diabetes or heart failure, puts you at even greater risk during the colder months.
Our Environment and Our Behavior
As a rule, humans are not fond of staying outside in the cold weather. It may be fun to participate in winter sports or play in the snow with the right clothing on, but eventually everyone wants to come in from the cold. Because this is a communal response, we tend to congregate inside buildings that are heated with dry air. So now we have a lot of people inside, breathing the same air that causes our nasal passages to become dry and cracked. During that time of the year, chances are that some of us will already be infected, even if we don’t have symptoms yet. So any coughing, sneezing, or running noses increases the chances of someone else getting sick. The dry air (whether inside in the heat or outside in the cold) also makes it easier for the viruses to get around. Trapped in tiny droplets of moisture that stay suspended even longer in dry air, these viruses are free to move around and find their way into someone’s respiratory system. If the rooms are poorly ventilated, which is often the case, the chance of more people getting infected goes up.
Can you think of anywhere that lots of people who might be carrying a virus are congregated routinely during the colder months? That’s right – school. From kindergarten to college, filled heated classrooms and dormitories create a perfect environment for “catching cold”. Hence, from fall to spring, both the cold and the flu have ample hunting grounds for human hosts.
What Your Primary Care Physician Knows that Will Keep You Healthy
So, viruses are more active in the cooler months, the environment helps to create a perfect breeding ground for airborne infections, and our natural survival instinct to keep warm increases our chances of getting sick. However, there are some other human behaviors that we can change to prevent some of these illnesses, and your primary care physician is a perfect place to look to for advice. The following are a few tips you should remember during cold and flu season.
First, try not to share. When you cough or sneeze, cover your mouth. Also make sure and wash your hands frequently, especially after coughing or using tissues; and keep your hands away from your face because every surface you touch has the potential of carrying germs. You can also protect others from illness. If you are sick, stay home until you are feeling better.
You should also be aware of your environment. Know that if you are in an enclosed or poorly ventilated space, you are more at risk. This would include offices, classrooms, dormitories, and airplanes. If you can, try to alter your environment by making sure there is good ventilation, and humidification.
Finally arm yourself to fortify your defenses. Eat a healthy ad well-balanced diet. You should also get daily exercise and plenty of sleep. However, one of the most important things you can do to help your immune system is by staying up to date with your vaccines. This includes the flu vaccine, which is available every year beginning in September. This vaccine is made from an inactivated virus. That means it is not alive and it cannot give you the flu. What it does, is provoke your body into making specific antibodies (fighting cells) against the most common flu virus strains for the season. The most common side effects are a sore arm, and possibly mild flu-like symptoms, which are caused by your immune system’s healthy response to the vaccine. The flu is a very serious illness that not only causes severe and prolonged symptoms, but also is responsible for many deaths each year. That is why your primary care physician will recommend that each person receive the vaccine each year, beginning at six months of age.
If you have any more question regarding cold and flu season, or how your primary care physician can help you stay healthy, we are happy to discuss this and any other healthcare concerns you may have. Please call Advanced Medical, PA, at (561) 434-1935 to request an appointment, or request one online.