Hyperventilation
From The Art and Popular Culture Encyclopedia
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Hyperventilation or overbreathing is the state of breathing faster than normal at rest (normal minute ventilation is generally 5-8 liters of air per minute at rest for a 70-kg man). It can result from a psychological state such as a panic attack, from a physiological condition such as metabolic acidosis, or can be brought about by lifestyle risk factors or voluntarily as in the yogic practice of Bhastrika.
Hyperventilation can, but does not necessarily always cause symptoms such as numbness or tingling in the hands, feet and lips, lightheadedness, dizziness, headache, chest pain, slurred speech, nervous laughter, and sometimes fainting, particularly when accompanied by the Valsalva maneuver.
Counterintuitively, such effects are not precipitated by the sufferer's lack of oxygen or air. Rather, the hyperventilation itself reduces the carbon dioxide concentration of the blood to below its normal level because one is expiring more carbon dioxide than being produced in the body, thereby raising the blood's pH value (making it more alkaline), initiating constriction of the blood vessels which supply the brain, and preventing the transport of oxygen and other molecules necessary for the function of the nervous system.
See also
- Hypoventilation, too shallow or too slow breathing
- Control of respiration
- Respiratory alkalosis
- Shallow water blackout, the role of hyperventilation in some drowning incidents
- Hyperpnea
- Tachypnea
