Which of the following is a known symptom associated with dyspnea?

Dyspnea is defined as a sensation of difficult or labored breathing and is a term often used to describe shortness of breath. The symptom most closely associated with dyspnea is difficulty breathing. This symptom encompasses the primary experience of the condition, highlighting the distress and increased effort required during breathing.

Chronic cough, hyperventilation, and chest pain can be related to various respiratory or cardiovascular conditions but are distinct from the direct experience of dyspnea. Chronic cough may indicate an underlying issue but does not define the sensation of difficulty in breathing. Hyperventilation involves rapid or deep breathing that may occur in response to anxiety or exertion and does not necessarily equate to the subjective feeling of having difficulty breathing. Chest pain can occur alongside respiratory distress but is a separate symptom and may indicate other conditions, such as cardiac issues. Therefore, the correct answer focuses directly on the essence of dyspnea: experiencing difficulty in the act of breathing itself.