Hyperventilation is rapid or deep breathing, usually associated with anxiety or panic. When you breathe, you inhale oxygen and exhale carbon dioxide. Rapid breathing or "overbreathing" may lower the levels of carbon dioxide in your blood so much that blood chemistry is affected, leading to abnormal neuromuscular function. This is the cause of symptoms you develop if you hyperventilate: chest pains, palpitations, dizziness, numbness or tingling, especially in the extremities and around the mouth. Muscles of the hands and forearms may cramp.
Most episodes of hyperventilation are brief, with no lasting effects. Chronic hyperventilation syndrome is different. Although it stems from "overbreathing," this usually isn't readily apparent to doctors or patients. Typically, however, patients sigh or yawn while otherwise seeming to breathe normally. They tend to focus on other physical symptoms - chest pain, feeling dizzy or faint, palpitations, digestive complaints, weakness, irritability and sleep disturbance among many others. Many suffer from obsessive-compulsive disorders, report sexual and marital problems, and have a hard time dealing with stress. What's more, their symptoms mimic those of serious medical disorders, which can lead to a lot of unnecessary medical tests and procedures before the real cause of the problem is found.
Patients diagnosed with chronic hyperventilation syndrome who have the best outcomes are those referred by their physicians for breathing retraining and those who learn to better manage stress. You mention Buteyko Breathing Therapy (BBT), developed by a Russian, Konstantin Buteyko, who linked hyperventilation to asthma and developed a technique to address it. BBT became known in the United States and Europe after it was introduced into Australia in the 1990s. BBT hasn't yet been well studied – I saw only 18 citations in a search of the medical literature with inconsistent findings. But I would say it's worth trying.
The RESPeRATE device, which is FDA approved for over-the-counter sale, is used to help patients lower their blood pressure by pacing their breathing. I haven't seen any evidence suggesting that it can be helpful for chronic hyperventilation syndrome, but, again, I would give it a try. I would also urge you to listen to my audio program, "Breathing: the Master Key to Self-Healing," and to practice the 4-7-8 Relaxation Breath that I teach. It has helped people with severe panic disorder, generalized anxiety, and many other problems.
Andrew Weil, M.D.