What is Anoxia?

Oxygen is essential for numerous processes in the body, including energy production and respiration. Anoxia is an extreme form of hypoxia or oxygen deprivation that can have serious consequences.

Woman with oxygen mask onRuslan Guzov | Shutterstock

Why is anoxia dangerous?

Anoxia is a dangerous condition that can have life-threatening consequences, with effects worsening with time. While hypoxia (a less extreme version of oxygen deprivation), can be experienced in under almost any circumstance, anoxia is typically triggered in high-altitude environments where oxygen levels are relatively low.

Several life-threatening conditions have been linked to anoxic or oxygen-deprived environments, such as myocardial infarction, stroke, and cancer. Studies also suggest that anoxia may increase the risk of cancer, as it creates a selective pressure for cells that can adapt quickly and grow in the absence of oxygen (anaerobic metabolism).  

The greatest danger caused by anoxia is brain damage, as cells in this area of the body are highly dependent on oxygen. The onset of anoxia in the brain can lead to dizziness, memory loss, and an increased risk of several conditions, including dementia.

Symptoms of anoxia

The onset of anoxia often goes unnoticed, as the patient experiences non-descript symptoms such as forgotten words, memory loss, and dizziness that could be associated with a number of other medical conditions.

Immediate exposure to oxygen-deprived environments may produce hypoxic or anoxic symptoms; however, continuous, low level exposure may delay the appearance of symptoms for a few days up to a few weeks.

Generally, people diagnosed with anoxia experience the following symptoms:

  • Decreased blood flow to vital organs, including the brain, kidney, heart, and tissues
  • Breathing difficulties
  • Cognitive changes (memory loss, altered states of judgment)
  • Headaches or dizziness
  • Difficulty with muscle movement
  • Physical weakness of the whole body

In more severe cases of anoxia, patients may also experience seizures or hallucinations. The sudden impact of anoxia may severely impact functional and occupational capacities that could lead to months or years of treatment.

Diagnosing and treating anoxia

When anoxia is suspected, physicians carry out a number of tests, including blood tests and neuroimagery, which confirm the diagnosis. Blood counting and blood gas testing are the most common forms of diagnostic tools used in confirming anoxia. For more severe cases, physicians may perform neuroimaging tests such as MRI, fMRI, or CT scan to generate a more detailed overview of the brain and determine the specific areas that have been affected.  

When physicians confirm a diagnosis of manageable anoxia, an inhaler is usually prescribed. However, when the case is more severe, a ventilator may be used. Treatment for brain damage and/or seizures may also be required, and is carried out by a specialist.

Further Reading

Last Updated: Dec 22, 2022

Gaea Marelle Miranda

Written by

Gaea Marelle Miranda

Gaea graduated from the University of the Philippines, Manila, with a degree in Behavioral Sciences, cum laude . Majoring in psychology, sociology, and anthropology, she approaches writing with a multidisciplinary perspective.


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