Which gives rise to a runny nose, everyone knows from their own experience. If not from influenza or acute respiratory infections, then from a cold - supercooling of the body. And what is the purpose of a person's cold? If it exists soon, it means something is needed for it.
Doctors have long noticed that a cold runny nose, not complicated by infection, lasts for some time. That's why they joke that untreated runny nose passes in three weeks, and treated runny nose - in twenty-one days*. True, the drops for the nose narrow the vessels of the mucous membrane, make it easier to feel better, but soon the nose again begins to lay the nose, again a runny nose. So why did our body appear and genetically fixed such unpleasant reaction?
Maybe someone calls other terms, but "on science" - three, not one, not two weeks, the author believes.
For thousands of years, man had to fight for existence, and perhaps the main danger for him were pathogenic germs. At the same time, numerous protective and counteractive forces were developed in the organism. There were "eaters" of microbes in blood - phagocytes, immunity and so on. But still the infection sometimes prevails, and then the body puts forward a second line of defense: fever, a persistent increase in body temperature kills some germs, and for others creates unfavorable conditions. In addition, fever activates the nervous system, vital tonus. And this is very important, because it increases the activity of all protective mechanisms.
However, high temperature is an extreme measure, the use of it without much need to the body is unprofitable. Often there are also such situations when there is no infection in the body yet, and the appearance of it is possible, and in anticipation of danger the body should strengthen protection. How does this happen?
There is another harmful factor - cold. Decrease in body temperature even by four to five degrees for life is not dangerous, but it sharply weakens the function of the higher parts of the brain, gives failure of protective mechanisms, and from here is not far and to the disease - because the gate for infection is open. It has long been established that one of the "keys" opening this gate is hypothermia. And since this weakens the function of the cortex of the large hemispheres, to mobilize the body's resistance, it must be activated, and then comes to the aid of the nose, or rather, enhanced and prolonged hydration of its mucous membrane - runny nose. How does this mechanism work?
The effect of cold on the body is rarely even. Usually, hands, legs, face and head are cooled down first of all. There is a difference in temperature between neighboring tissues. And this, as it turned out, becomes the "trigger" of the cold. You can catch a cold on a hot day, if you sit hot and sweaty on the draught.
As a result of hypothermia, peripheral spasm occurs and the vessels of the nasal mucous membrane expand. Blood overfilling (called hyperemia - full-blooded) increases the permeability of capillary walls. The liquid part of the blood is as brackish as tears, as if sweating through the walls of blood vessels, intensely moisturising the mucous membrane and irritating its receptors. More intensively working mucous glands. This leads to a runny nose.
Swollen mucous membrane reduces the lumen of the nasal passages, breathing becomes more difficult, and the narrowed air flow more irritates the moistened receptors. In this way, the body reaches the desired goal - increases the flow of impulses to the brain, increases the excitement of its higher parts.
Most likely, a cold cold is the first preventive measure in anticipation of possible infection. It is not yet a disease, but a pre-disease. Therefore, people with weakened protective functions more often catch cold. If "runny nose protection" is ineffective, the next barrier is fever. It should be remembered that a fever of one to two degrees helps to fight the disease, so do not bring down the fever. The fever needs to die when the mercury column approaches 39...40°.
Often surprised: there is no flu, ORZ, too, did not catch cold ... where does the cold come from?
It turns out that increased hydration of the nasal mucous membrane is required for the body to increase the efficiency of cortical neurons if necessary. In elderly people it is weakened, so - worried ... and you have to take out a handkerchief. It's worth it to calm down and run out of runny nose.