What physiological change is likely to increase in adults experiencing breathing difficulty?

When an adult experiences breathing difficulty, a commonly observed physiological change is an increase in respiratory rate. The body reacts to inadequate oxygenation or the presence of carbon dioxide buildup by trying to compensate for these issues. When breathing becomes more labored or ineffective, the respiratory system attempts to increase the rate at which a person breathes to enhance gas exchange and deliver more oxygen to the tissues while expelling carbon dioxide.

An increase in heart rate can also occur during respiratory distress as a compensatory mechanism, but it is not the direct physiological change indicated by breathing difficulty itself. Similarly, pulse rate is an expression of heart rate, and while it may also increase, it is not as direct a response as the increase in respiratory rate in this context. Temperature changes are typically unrelated to immediate respiratory distress and would be more indicative of an underlying infection or illness rather than a direct response to difficulties in breathing.

Thus, the increase in respiratory rate is the primary physiological response to breathing difficulty as it directly addresses the body’s need for oxygen and the elimination of carbon dioxide.