Dynamic obstruction is a medical term referring to a reduction in the patency of the airways, which can vary depending on various factors. This means that the airways, which are usually open and allow the flow of air in and out of the lungs, narrow or become blocked. The narrowing of the airways can be triggered by various factors, such as allergens, infections, physical activity, or even stress. Symptoms may include difficulty breathing, coughing, choking, etc.