When the weather is cold, be elegant, not warm. Won't young people catch a cold and get sick with less clothes?

No, a cold has nothing to do with cold weather, nor does it have anything to do with blowing (whether hot or cold), bacteria, immunity and so on. A cold is only related to one thing, that is, the cold virus.

I often catch a cold in winter not because the weather is cold, but because the air is too dry. If the indoor and outdoor air is too dry, the cold virus will float in the air and easily enter people's nasal cavity. If you have a cold virus on your hand, picking your nose and rubbing your eyes will also make the cold virus enter the nasal cavity (the cold virus that enters your eyes reaches the nasal cavity through the lacrimal duct).

There are cilia on the nasal mucosa, which will swing back and forth and send things stuck to it to the nasopharynx. In this way, the virus that enters the nasal cavity is sent to the adenoids, that is, the lymphatic tissue at the back of the nasal cavity. There is a receptor called intercellular adhesion molecule (ICAM) on the surface of adenoid cells. The receptor has a ligand that specifically binds to it, but the cold virus can disguise itself as the ligand of ICAM, bind to ICAM, and let ICAM send it into the cell.

After the cold virus enters the adenoid cells, it hijacks the cells and replicates the virus in large quantities by using the equipment in the cells. Infected cells eventually die and rupture, releasing newly replicated viruses to infect other cells. The cold virus is highly contagious, and a small amount (1 ~ 30 cold virus particles) is enough to cause infection. Once the cold virus enters the nasal cavity, 95% people will be infected.

If the weather is too cold, keep warm properly, and be afraid of getting sick (cold will hardly cause disease) and frostbite.

If the weather is cold and you wear less clothes, some people may sneeze and have a runny nose. This is a normal physiological phenomenon, not a cold or disease. Wear more clothes or go to places with high temperature, and these phenomena will disappear.