Hypoxia is a pathological condition in which the body as a whole (generalized hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply.

Hypoxia is often associated with high altitudes, where it is called altitude sickness.

Symptoms of generalized hypoxia depend on its severity and speed of onset. They include headaches, fatigue, shortness of breath, nausea, unsteadiness, and sometimes even seizures and coma.

Categories of hypoxia:

• Cerebral hypoxia in which the brain is deprived of oxygen despite normal blood flow.
• Hypoxic hypoxia in which arterial oxygen pressure is reduced.
• Anemic hypoxia in which arterial oxygen pressure is normal, but total oxygen content of the blood is reduced.
• Ischemic hypoxia in which blood flow to the tissues is too low.
• Histotoxic hypoxia in which quantity of oxygen reaching the tissue is normal, but the tissue is unable to use the oxygen.

See also

• Asphyxia
• Hypoxic tumor