There are four main types of hypoxia: hypoxic, anemic, stagnant, and histotoxic hypoxia. Each type is characterized by specific changes in arterial oxygen levels, hemoglobin levels, blood flow, and tissue oxygen use. Hypoxic hypoxia involves reduced oxygen at the lung or tissue level, anemic hypoxia occurs when hemoglobin levels decrease, stagnant hypoxia is due to decreased blood flow, and histotoxic hypoxia impacts the tissues' ability to use oxygen. The body responds to hypoxic conditions through acclimatization mechanisms like hyperventilation and increased red blood cell production, though these only partially restore normal oxygen levels. Long-term hypoxemia treatment for lung diseases has been