Oxygen deficiency


Oxygen deficiency will occur when we breathe in air that is less the 20% oxygen by volume, with the most common type of deficiency being hypoxia which is commonly seen in people climbing mountains like Everest or in patients on an ITU ward. Even tiny amounts of oxygen decreases can cause issues and produce symptoms.

We can experience this lack of oxygen for many reasons but could include:

  • low arterial blood oxygen concentration
  • bronchitis
  • asthma
  • pneumonia
  • COPD
  • hyperventilation
  • abnormal levels of haemoglobin and plasma
  • exposures to gases in the air such as carbon monoxide, methane and hydrogen sulphide
  • anxiety
  • sustained periods of strenuous activity which may affect breathing habits


The breakdown below outlines what may occur during different stages of being starved of oxygen:

  • 15-19% - people may start to experience a lack of coordination. This is because tissues are not getting the oxygen needed to perform basic metabolic processes.
  • 10 or 12% - a person’s lips can turn blue and their judgment becomes seriously impaired.
  • 8-10% - an individual may faint or become unconscious.
  • 6-8% - if you experience this level for only eight minutes it could cause death.