Hypoxia generically means a low level of oxygen. In different contexts it may refer to:

In the body:

• Hypoxia, the reduction of oxygen in tissues below levels which are considered to be normal.
• Hypoxaemia, the reduction of oxygen specifically in the blood.
• Hypoxic hypoxia, hypoxia resulting from a defective mechanism of oxygenation in the lungs.
• Anoxia the extreme form of hypoxia where there is no oxygen present, an anoxic condition.
• Anaemic hypoxia is a state where the oxygen content of blood is low and the cause is anaemia, a decrease in the amount of haemoglobin in the blood.
• Cerebral hypoxia also cerebral ischemia, is a pathological condition called hypoxic encephalopathy, a hypoxic condition in which there is a decrease of oxygen supply to the brain.
• Ischemia is a medical term for hypoxia where there is a restriction in blood supply, generally due to factors in the blood vessels. Also ischaemia or ischæmia.

In the environment:

• Environmental hypoxia or oxygen depletion, a reduced concentration of dissolved oxygen in a water body leading to stress and death in aquatic organisms.
• Hypoxic zones, or dead zones, are hypoxic areas in the world's oceans.
• Anoxic sea water is a condition where there is an abnormally low level of oxygen in the sea.
• The oxygen minimum zone is the depth in the sea at which the disolved oxygen level is lowest, or most hypoxic.
• Oxygen saturation is a relative measure of the amount of oxygen that is dissolved or carried in a given medium and is therefore a measure of hypoxia or hypoxic conditions.

Hypoxie