How should breathing be managed during a descent to mitigate hypoxia?

Maintaining a steady and deep breathing pattern is crucial during a descent to mitigate hypoxia. When a pilot or passenger is exposed to a rapid decrease in altitude, the atmospheric pressure drops, leading to a decrease in the partial pressure of oxygen available for breathing. This reduction can result in hypoxia, where the body and brain do not receive enough oxygen.

Deep and steady breathing helps to maximize oxygen intake by ensuring that more air, including oxygen, reaches the lungs and is delivered to the bloodstream. This practice increases the volume of air exchanged in each breath, allowing for better oxygenation of blood and thus helping to prevent or alleviate symptoms of hypoxia.

In contrast, breathing quickly and shallowly may not provide sufficient oxygen and can lead to increased carbon dioxide retention, which might exacerbate feelings of lightheadedness or dizziness. Holding one's breath can further diminish oxygen levels and is dangerous in a rapidly changing environment. Breathing only through the nose may also limit airflow and reduce overall oxygen intake, thus failing to provide the deep, adequate breaths needed to counteract hypoxia effectively.