Why does a person start to have a runny nose when he is cold?

Because people get cold air into their noses, they will have a runny nose when they are hot. The reason has a lot to do with the change of environment.

As the weather gets cold, slugs become demons again, which makes us have slugs all the time. 50%-90% people have a runny nose when they are cold all day. If they eat or walk faster, it may cause them to keep smelling and running, and their runny nose will flow freely.

Under normal circumstances, nasal mucus flows to the back nostril and pharynx along the movement direction of nasal mucosa cilia, a small part evaporates, and a small part becomes nasal excreta after drying. Generally, it can't be seen from the nasal cavity. No matter in the process of heating or humidifying the air, the temperature of the nasal cavity will drop again because of the evaporation of water, so the nose will feed back to the brain and apply for heating. The brain will further increase the blood supply and fluid secretion in the nasal cavity.

As patients with rhinitis, asthma, eczema or hay fever, the cells in their nasal cavity are more sensitive, so in this process, they will also have more extreme reactions, so their noses will get out of control. Generally speaking, people without rhinitis usually have obvious runny nose and slight nose swelling in winter. As long as people reach normal body temperature, the situation will get better.

In addition, cold air can irritate eyes and cause tears, but if there are not enough lacrimal glands to form tears, the liquid secreted by lacrimal glands will flow into the nose from the nasolacrimal duct, which will also increase the number of runny noses, which is called "a runny nose and a tear". Therefore, in order to prevent embarrassing situations, try to wear a mask when going out in winter to reduce cold air from entering the nasal cavity and keep warm. You can wash your nose with salt water when you have a runny nose.