A serious respiratory problem that an anxious, stressed diver may have either while underwater or at the surface is called _____.

The correct answer highlights a condition referred to as hyperpnea, which is characterized by an increased rate and depth of breathing. This can occur in response to physical exertion or emotional stress, such as anxiety that a diver may experience either while submerged or upon surfacing. When a diver becomes anxious or stressed, their breathing may become rapid and shallow, which could lead to hyperventilation. This condition can further exacerbate feelings of panic or discomfort, making it a significant concern for divers.

Understanding hyperpnea is essential in the context of diving, as it can impact a diver's air consumption and carbon dioxide levels, potentially leading to more serious complications if not managed appropriately. It highlights the importance of proper breathing techniques and the need for mental preparedness in diving.

The other choices, while they may relate to respiratory issues or diving problems, do not specifically refer to the scenario described in the question. For example, hypoxia is related to insufficient oxygen, asthma is a chronic respiratory condition, and decompression sickness pertains to a different set of risks associated with diving. Each of these conditions has its own implications and wouldn’t typically be categorized as a direct response to anxiety and stress in the way hyperpnea is.