What is hyperventilation?

Quick Answer
Breathing at a faster rate than what is needed for metabolism, resulting in the exhalation of carbon dioxide faster than it is produced.
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Causes and Symptoms

Hyperventilation is rapid deep or quick shallow breathing, both of which can result in a dramatic decrease in carbon dioxide levels and an increase in the pH of the blood. While its purpose is an attempt to get more oxygen, hyperventilation can actually result in feeling breathless or dizzy and, in extreme cases, fainting.

There are several possible causes or reasons for hyperventilation, including anxiety, panic attacks, agoraphobia (fear of open spaces), depression, anger, and overconsumption of caffeine. Hyperventilation can also be a symptom of an underlying disease process such as an infection, bleeding, or heart and lung disorder, as well as a response to altitude exposure. Hyperventilation syndrome (HVS) can be manifested either acutely or chronically.

Chronic HVS can cause a variety of physical problems involving respiratory, cardiac, neurologic, or gastrointestinal (GI) systems. Aerophobia, a fear of fresh air, brings on the GI problems such as flatulence, bloating, and belching. Besides rapid breathing, hyperventilation can cause a fast pulse, shortness of breath, chest pain or tightening, dry mouth (from mouth breathing), numbness around the lips and hands, and, in more severe cases, blurred vision, seizures, and loss of consciousness. The chest pain resembles typical angina but does not usually respond to nitroglycerine. Changes in the patient’s electrocardiogram (ECG) are common, including ST segment elevation or depression, T-wave inversion, or a prolonged QT interval. Patients with mitral valve prolapse are particularly susceptible to HVS. On occasion, hyperventilation can also be manifested with extreme agitation, tingling in the extremities, or painful hand and finger spasms. The chief characteristic of chronic HVS is multiple complaints without supporting physical evidence. Hence, classic hyperventilation is not readily apparent, but frequent sighing may be evidenced, along with chest wall tenderness, numbness, and tingling sensations. To rule out more serious conditions, arterial blood gases, toxicology screens, and chest X rays are suggested.

Hyperventilation is a technique purposefully used by swimmers and deep-sea divers to enable prolonged breath-holding. Many drownings have been related to this practice, however, because it can cause delayed unconsciousness underwater and subsequent death.

Treatment and Therapy

Contrary to popular belief, breathing into a paper bag to slow down respiration and retain carbon dioxide is not recommended as a treatment for hyperventilation because of the potential life-threatening aggravation of a more serious medical problem such as hypoxia, a myocardial infarction (heart attack), pneumothorax, or pulmonary embolism.

After life-threatening causes of hyperventilation are eliminated, the most successful treatment for hyperventilation is reassurance, discussion of how hyperventilation is causing the patient’s symptoms, and removal of the cause of the anxiety, if possible. Instructions from a respiratory therapist on proper abdominal diaphragmatic breathing are also helpful. A patient who faints should be placed flat on the floor with legs elevated. For more severe recurrent cases, antidepressants, beta-blockers, stress management classes, or breathing retraining have all been proven effective in reducing hyperventilation episodes.


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