Carbon dioxide, or CO2, is a normal product of metabolism within the body’s cells. The blood carries this carbon dioxide waste to the lungs to be exhaled out of the system. When there is an elevated level of CO2 within the blood, complications occur. Doctors refer to this medical condition as hypercapnia, or hypercarbia. This can occur through health problems, environmental exposure to carbon dioxide or unsafe scuba diving practices or faulty diving equipment.

Shortness of Breath

Too much carbon dioxide within the blood causes the body’s pH level to plummet and become dangerously acidic, explains Auburn University at Montgomery School of Sciences. The higher the acidic quality, the more difficult it is for the blood’s hemoglobin to pick up oxygen. The result is rapid breathing in order to increase lowered oxygen levels and, eventually, difficulty in catching one’s breath.

Headache

A study revealed in a report by the U.S. Environmental Protection Agency (EPA) exposed 42 volunteers to inhalation of 7.6 and 10.4 percent of carbon dioxide within 2.5 to 10 minutes. Headaches were a common adverse effect experienced by the study group individuals.

Increased Heart Rate

The human body reacts to carbon dioxide retention. As available oxygen lowers and carbon dioxide levels begin to rise, receptors within the body sense a problem and send messages to the heart to beat faster, according to Auburn University. This is an attempt to increase the amount of blood going to the lungs in hopes that CO2 is released and more oxygen inhaled.

Dizziness or Confusion

In the same study results revealed by the EPA, the other most common side affect from excessive carbon dioxide exposure was dizziness. Those who inhaled high concentrations in only one minute had initial dizziness and then experienced bouts of confusion and inability to focus or reason.

Seizures

If 30 percent or more of carbon dioxide is inhaled, the body begins to convulse within 1.5 minutes, states the EPA. By this time, the body is unable to get rid of the carbon dioxide and obtain oxygen fast enough on its own. The body’s receptors begin to lose control of body movement.

Unconsciousness or Coma

Humans exposed to high concentrations of carbon dioxide in a short time frame can experience catastrophic, lethal effects, according to the EPA. Instant exposure to 17 to 30 percent of CO2 after only one minute can result in unconsciousness and coma.

Respiratory Arrest

Medical conditions which cause weakening of the lungs can result in dangerously high levels of carbon dioxide. If the muscles are not strong enough to expand the lungs to sufficiently inhale, only a small amount of air and little to no carbon dioxide is exhaled. If untreated, this leads to lower and lower oxygen levels and eventually, cessation of breathing.