How does altitude affect respiratory function?

At higher altitudes, the atmospheric pressure decreases, which in turn reduces the partial pressure of oxygen in the air. This reduction means that less oxygen is available for the body to use during respiration. Consequently, the efficiency of gas exchange in the lungs is negatively impacted, leading to lower oxygen availability in the bloodstream. This physiological challenge can result in symptoms such as shortness of breath and fatigue as the body struggles to obtain enough oxygen.

The body's response to these conditions includes increased respiratory rate and depth in an attempt to compensate for the lower oxygen levels. Over time, individuals may experience acclimatization, where adaptations occur to improve oxygen delivery and utilization, but initially, the decreased partial pressure of oxygen directly leads to diminished respiratory efficiency. This physiological dynamic is why the choice indicating that reduced oxygen pressure at higher altitudes may decrease respiratory efficiency is the most accurate reflection of how altitude affects respiratory function.