The Link Between Carbon Dioxide Retention and Sleep

Carbon dioxide is a colorless, odorless gas that is retained in the blood when sleep disorders occur. Its chemical compound consists of one atom of carbon covalently bonded to two atoms of oxygen. Carbon dioxide is represented by the chemical formula CO2 and is commonly referred to as such instead of by its full name.

Woman asleep in bed
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How Does Carbon Dioxide Form?

It may form by the burning of carbon or organic materials and is sometimes referred to as the greenhouse gas, with a role in climate change. It naturally makes up about 0.04 percent of air. It is absorbed by plants during photosynthesis.

Carbon dioxide is also created by metabolism within the human body and it is principally removed via expiration from the lungs. It, therefore, can build up in the blood when breathing becomes disrupted. High levels of carbon dioxide may cause drowsiness and—at the most extreme levels—unconsciousness, coma, and death.

Carbon Dioxide Retention as a Byproduct of Sleep Disorders

The retention of carbon dioxide in the blood is an important consequence of a handful of sleep disorders that affect breathing, especially sleep apnea, central hypoventilation syndrome and obesity hypoventilation syndrome.

Sleep apnea, reportedly the second most common sleep disorder, can cause people to suddenly stop breathing while they are asleep. When this happens, carbon dioxide accumulates in the blood, causing the sleeping person to wake up to gasp for breath. How long a person stops breathing as a result of sleep apnea can range from a matter of mere seconds too long enough that the individual's skin becomes blue as the result of oxygen deprivation.

Many of the estimated 20 million Americans who have sleep apnea may not realize they suffer from the disorder.

Routinely waking up with morning headaches may be a sign of sleep apnea. The headaches stem from difficulty breathing while sleeping.

There are numerous other causes for morning headaches as well. They include muscle tension, nasal congestion or allergies.

Sleep and Carbon Dioxide Retention

Carbon dioxide retention is called hypercapnia, Many people have no symptoms of hypercapnia, but if they do, they're likely to feel drowsy or find it hard to think straight. Severe hypercapnia, on the other hand, can cause noticeable symptoms, such as increased heart rate, blood pressure, or muscle twitches. It can lead to respiratory failure if untreated.

Wrapping Up

If you're concerned that you have sleep apnea or another sleep disorder, discuss your symptoms with your practitioner. Let your healthcare provider know that you're concerned about the possibility of carbon dioxide building up in your body.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. NASA Global Climate Exchange. The Atmosphere: Getting a Handle on Carbon Dioxide.

  2. Wisconsin Department of Health Services. Carbon Dioxide.

  3. Antoine M, Katyal N, Bollu PC. Ventilation Obesity-Hypoventilation Syndrome. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from:

  4. National Heart, Lung and Blood Institute. Sleep Apnea.

  5. Patel S, Majmundar SH. Physiology, Carbon Dioxide Retention. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from:

By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.