What Is Asphyxia?

Medically Reviewed by Jabeen Begum, MD on November 29, 2021

Asphyxia happens when your body doesn't get enough oxygen to keep you from passing out. It can be a life-threatening situation.

When you breathe normally, first you take in oxygen. Your lungs send that oxygen into your blood, which carries it to your tissues. Then your cells use it to make energy. Any interruption to the process of breathing in oxygen or breathing out carbon dioxide can make you pass out or even lose your life.

Physical Asphyxia

One type of asphyxia is called "physical" or "mechanical." It happens when a­­ force or object keeps you from breathing.

Lots of accidents can lead to it. Some examples of physical asphyxia are:

Choking. This is when food or an object gets stuck in your airway and blocks air from getting to your lungs. The elderly have a greater chance of this happening to them, especially those who live alone, wear dentures, or have trouble swallowing. Babies and toddlers also have higher odds of choking on large pieces of food or things they put in their mouths.

Aspiration. It's different from choking. Aspiration happens when something you eat or drink "goes down the wrong pipe" and enters your airway or lungs. The substance crowds out the air in your body. Drowning is the most common type of aspiration.

Suffocation (smothering). Suffocation happens when something heavy covers the face or chest and prevents you from breathing. It also occurs when you are in a place where oxygen runs out, such as a closed-in, airtight space.

Strangulation. If a cord or rope or other object long enough to go around your neck presses on the airway, it blocks air from getting to your lungs.

Drug overdose. Opioids affect your breathing. When you take too high a dose, it can slow down your breathing to the point that your body does not take in enough oxygen.

Birth asphyxia. Sometimes, an unborn child may get too little oxygen during pregnancy. This might happen, for example, because of a lack of oxygen in the mother's blood, or problems with the placenta. During delivery, the baby can also not get oxygen because of umbilical cord problems or a long labor.

Seizure. It can cause asphyxia in several ways. Epileptic seizures may make your breathing suddenly pause (also called apnea), and lower oxygen in your body to life-threatening levels. Also, during a seizure, your body may move in such a way that your airway gets covered, blocking your breathing.

Illnesses or injuries, like heart failure, a broken neck, or an allergic reaction that causes airways to swell and close, can also cause physical asphyxia.

Chemical Asphyxia

Another type of asphyxia is called "chemical." In this type, a chemical keeps oxygen from reaching your cells.

Chemicals that can cause asphyxia include:

Carbon monoxide. This is a colorless, odorless gas that comes from burning different types of fuel. If you breathe in too much of it, the gas builds up in your body and replaces the oxygen in your blood.

Cyanide. It keeps cells from taking oxygen in. You're at risk of cyanide poisoning if you breathe smoke during a fire, have contact with certain industrial chemicals, or work in jobs like mining or metalworking.

Hydrogen sulfide. This gas smells like a rotten egg. It can come from sewage, liquid manure, sulfur hot springs, and natural gas. If you breathe in too much, it can prevent oxygen from entering your cells, much like cyanide does.

Show Sources


Medscape: "Pathology of Asphyxial Death."

Mayo Clinic: "Carbon Monoxide Poisoning."

National Safety Council: "Choking Prevention and Rescue Tips."

The National Center for Fatality Review and Prevention: Suffocation, Choking and Strangulation."

MedlinePlus: "Opioid Overdose."

Seattle Children's Hospital: "Birth Asphyxia."

CDC: "Sudden Unexpected Death in Epilepsy."

© 2021 WebMD, LLC. All rights reserved. View privacy policy and trust info