What can cause hypoxic hypoxia?

Hypoxic hypoxia refers to a condition where there is insufficient oxygen in the blood to meet the body's needs, primarily due to low levels of oxygen in the environment or issues with the respiratory system. High altitude provides a classic example, as the atmospheric pressure decreases with elevation, leading to lower oxygen levels available for breathing. This can result in inadequate oxygenation of the blood, hence contributing to hypoxic hypoxia. Additionally, lung diseases can impair the gas exchange process by restricting airflow or damaging the alveoli, further exacerbating the issue of low oxygen levels in the blood.

In this context, while carbon monoxide poisoning can lead to a form of hypoxia, it primarily does so through the disruption of oxygen transport in the blood rather than a decrease in available oxygen in the environment. Anemia related to blood loss affects the oxygen-carrying capacity of hemoglobin but does not cause a deficiency in the oxygen available for respiration itself. Prolonged sitting, while it might lead to other circulation issues, does not directly cause hypoxic hypoxia. Therefore, high altitude and lung disease are directly related to causing hypoxic hypoxia through a decrease in available oxygen or ineffective gas exchange in the lungs.