Which of the following is a sign of poor respiratory function?

An increased heart rate is a typical physiological response to poor respiratory function. When the body is not receiving adequate oxygen or when there is an increase in carbon dioxide levels due to compromised breathing, it compensates by accelerating the heart rate to maintain adequate blood flow and oxygen delivery to vital organs. This compensatory mechanism indicates that the body is working hard to meet its oxygen demands, reflecting a situation where respiratory function is not optimal.

In contrast, normal skin color, clear lung sounds, and a calm demeanor suggest good respiratory health. Normal skin color indicates effective oxygenation, clear lung sounds imply unobstructed airways and functioning lung tissue, and a calm demeanor can suggest adequate oxygen levels and stable respiratory function. Thus, the presence of an increased heart rate serves as a significant indicator of potential respiratory distress or inadequate respiratory function.