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How Much Is Too Much Oxygen?

Published on Jan 05, 2023 and last reviewed on Feb 20, 2023   -  4 min read


Oxygen is an essential gas present on the planet earth. Read the article below to learn more about problems related to oxygen.


Oxygen is a non-metallic, colorless, odorless, tasteless gas essential for life. Oxygen was first discovered by the Swedish chemist Carl Wilhelm Scheele in 1772. However, inhaling oxygen at higher than normal partial pressures leads to oxygen toxicity or poisoning. Breathing excessive oxygen can result in severe health-related problems. Oxygen toxicity occurs when people ingest too much oxygen into their system, causing a cough, trouble breathing, or even lung damage. Hyperoxia and hypoxia are the terms used to describe problems associated with oxygen toxicity. Hyperoxia is a state of excess oxygen supply in the tissues and organs, and hyperoxemia refers to vasoconstriction and decreased cardiac output due to oxygen transport.

What Is Oxygen Toxicity?

Oxygen toxicity is a condition caused by excessive inhalation of oxygen, resulting in harmful effects on the body. It can also lead to some severe life-threatening conditions. Oxygen toxicity is a main concern for underwater divers, ventilated patients, and people undergoing hyperbaric oxygen therapy. Oxygen toxicity results in hyperoxia which refers to the excessive accumulation of oxygen in the body tissues. Due to this accumulation of oxygen in the body tissues, the body starts reacting in a different way and involves various systems of the body, like the central nervous system, pulmonary system, and vision changes. The central nervous system effects caused by oxygen toxicity are known as the Bert effect. It is caused by hyperbaric oxygen therapy in a dose-dependent correlation. The phenomenon of oxygen toxicity affecting the pulmonary system is known as the Smith effect, and it is caused by prolonged exposure to oxygen. There are some chemicals, such as chemotherapeutic agents named – Bleomycin, that can also increase the risk of oxygen toxicity.

What Are the Types of Oxygen Toxicity?

Oxygen toxicity can be divided into two categories -

  1. Acute Oxygen Toxicity - It is described as when a person is getting exposed to a very high concentration of oxygen for a short period of time.

  2. Chronic Oxygen Toxicity - It is defined as when a person is exposed to lower concentrations of oxygen but for a longer period of time.

What Are the Causes of Oxygen toxicity?

The primary causes of oxygen toxicity are

What Are the Signs and Symptoms of Oxygen Toxicity?

Oxygen toxicity can cause some serious symptoms associated with the respiratory and nervous systems and visual changes.

Nervous System

  • Dizziness.

  • Blurred vision.

  • Nausea.

  • Uncomfortable feeling.

  • Confusion.

  • Convulsions (seizure).

  • Headache.

  • Anxiety.

  • Disorientation.

  • Fatigue.

  • Twitching.

Pulmonary System

  • Coughing.

  • Breathing difficulties.

  • Fever.

  • Hemoptysis (presence of blood in vomit).

  • Chest pain.

  • Mild throat infection.

  • Chest burning.

  • Pulmonary edema.


  • In premature newborns, retinopathy of prematurity and retrolental fibroplasia.

  • Retinal edema.

  • Cataract.

It is very important to identify the above signs and symptoms early to prevent serious damage and seek medical attention.

What Happens to the Body During Oxygen Toxicity?

When a person breathes, oxygen from the air enters the lungs and goes into the blood. The oxygen travels to all parts of the body through the blood present in the arteries and veins. It keeps organs and tissues working at full efficiency. But high levels of oxygen content in the air can harm lung tissues. The tiny air sacs in the lung may fill with fluid or they may lose their ability to infiltrate. The lungs then can not take in the air normally. It becomes tough for the lungs to send oxygen into the blood. Oxygen toxicity can also affect the central nervous system symptoms.

How to Diagnose Oxygen Toxicity?

If an individual is admitted to the hospital on a ventilator, the blood oxygen level is measured by a device placed on a finger or toe or healthcare staff may collect the blood samples. The healthcare provider will ask about the patient’s health history and do a physical examination.

The healthcare provider may ask the patient to perform some investigations -

  1. Oxygen Saturation - In cases of oxygen toxicity, it is very important to monitor the blood oxygen levels.

  2. Imaging Test - This involves a chest X-ray to determine the conditions of the lung and its tissues, and in severe conditions, a CT scan (computed tomography) can also be performed.

  3. ECG (electrocardiogram) - The effect on the central nervous system is associated with tachycardia. Performing ECG will help to record the irregular heartbeat.

How to Treat Oxygen Toxicity?

The treatment of oxygen toxicity depends on the patient’s condition and associated signs and symptoms. The basic treatment is to stop the oxygen supply if the patient is hospitalized or works as a scuba diver. Oxygen toxicity affecting the body requires symptomatic treatment. In patients with hyperbaric oxygen treatments, those at high risk may get help from anti-epileptic therapy, prolonged air breaks, and limited treatment pressure. The administration of exogenous antioxidants, vitamins E and C, can help infants in hyperbaric therapy.

How to Prevent Oxygen Toxicity?

Oxygen toxicity can be prevented by eliminating the amount of oxygen in supplemental breathing sources. Preventing oxygen toxicity just requires awareness. Patients can measure blood oxygen levels to ensure they are treating their illnesses within safe guidelines. Blood oxygen levels can be measured using a pulse oximeter. This non-invasive device can be used at home to determine if the blood oxygen saturation has reached a tipping point toward oxygen toxicity. When a person uses supplemental oxygen regularly, relying on this simple gauge help measure and maintain healthy oxygen levels.


Oxygen is one of the most important things for all living organisms. The earth‘s atmosphere has 21 percent of oxygen. Oxygen toxicity is a rare problem, but people undergoing some treatment or practicing scuba diving are at higher risk. Oxygen toxicity can cause various complications affecting multiple organ systems. It can result in some serious health-related conditions involving various systems of the body. Oxygen toxicity is preventable by maintaining the level of oxygen during supplemental breathing sources. If an individual experiences this problem or associated symptom, seek medical help to avoid unfortunate circumstances.

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Last reviewed at:
20 Feb 2023  -  4 min read




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