What Are the Causes of Low Carbon Dioxide in the Blood?

Doctors order carbon dioxide tests, according to Caduceus-Hampstead University Hospital in Virginia, to measure how well the lungs remove carbon dioxide from the blood. Carbon dioxide (CO2) is a waste product of metabolism. When respiration increases, carbon dioxide levels drop. Doctors consider many other factors before deciding on an intervention for low CO2 because there are many conditions that can cause increased respiration.

Stress and Anxiety

Stress and anxiety can cause decreased carbon dioxide output. Just having a medical appointment or a lab test is stressful for some people. Dr. Jonnathan Busko, medical director of Northeast Maine Emergency Medical Services, says that hyperventilation is a major cause of low carbon dioxide output in the body. The cause also could be metabolic.


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The medicines you take can affect a carbon dioxide test. Antacids, diuretics, corticosteroids, hormones or barbiturates affect carbon dioxide output, according to Drugs.com. Caffeine and other stimulants, and too much aspirin, can increase respiration.

Underlying Conditions

Disease often produces metabolic issues. Some problems that might cause increased respiration, according to labtestsonline.org, are Addison's disease, diarrhea, uncontrolled diabetes, kidney disease and pneumonia. Certain environmental conditions, such as an overheated room, can temporarily increase respiration.

The Bottom Line

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If you have healthy lungs and kidneys, a low carbon dioxide level may have little significance--and no doctor makes a diagnosis based on a single lab value. Nevertheless, you should ask him about the relationship between your laboratory results and any underlying illnesses you might have, especially if you experience difficulty concentrating or catching your breath. If you have episodes of losing consciousness, seek immediate medical attention.