Bronchitis is a medical term for chest colds. Viral infection is the most common cause of acute bronchitis. Dr. Alan Greene, a pediatrician and paediatric clinical professor at Stanford University, pointed out that the study showed that cold air itself does not cause a cold or bronchitis. Although you must be exposed to infectious organisms to treat bronchitis, running in the cold can make you more susceptible to illness if you have a cold.

Acute bronchitis
Acute bronchitis is caused by a viral or bacterial infection that causes bronchial inflammation. These tubes swell and produce excessive mucus, which can irritate the lungs and cause painful GH. In addition to coughing, you may have headaches, body aches, fever and sore throat. When you cough, you may produce yellow or green mucus. Severe bronchitis can cause wheezing or shortness of breath.
Running and Immune System
Strenuous exercise such as running reduces the immune system. A position statement issued by the International Movement and Immunology Society in the 2011 Review of Sports Immunology states that acute strenuous exercise may inhibit antibody production and T cell production. T cells are one of the systems in which the body fights infection. White blood cells, another anti-infective mechanism, increase immediately after strenuous exercise but fall to low levels before returning to normal. When white blood cells are low, immunity to infection is reduced.
Hot and cold exercise
Exercise in extreme environments such as extremes, cold or high altitudes can increase the body's stress response and promote developmental respiratory infections such as bronchitis. The results reported in the December 2003 issue of the journal Aviation, Aerospace and Environmental Medicine indicate that exercise can produce immune disorders under extreme heat or cold conditions. The high temperature ambient temperature is 100 degrees Fahrenheit, the relative humidity is 45%, the cold is 46 degrees, and the relative humidity is 50%.
Cold Air and Mucous
Dr. Greene says cold air can affect the mucus transport system. Your respiratory system covers a thin g-mud called a mucus blanket that captures viruses and finesBacteria and other organisms. Running in cold air increases mucus production, but it also thickens it, so removing mucus is more difficult. Bacteria and viruses in mucus are in contact with the lungs for a longer period of time, which may increase the risk of infection.
Nasal congestion and histamine
Breathing cold air through the nose also increases nasal congestion and nasal congestion Dr. Green said that sultry heat makes it harder for the body to remove inhaled bacteria and viruses. Cold air can also cause the release of a chemical called histamine, which can cause wheezing or exercise-induced asthma. If you are running in col, all combinations of these factors increase the risk of bronchitis and expose the body to infectious organisms. Green recommends that you breathe through your nose while running and drink plenty of water to help keep your mucus thin.