Breath: Encyclopedia II - Breath - Control of Breathing

Breath - Control of Breathing

Breathing is one of the few bodily functions which, within limits, can be controlled both consciously and unconsciously. Conscious attention to breathing is common in many forms of meditation, specifically anapana. In music, breath is used to play wind and brass musical instruments and many aerophones. Laughter, physically, is simply repeated sharp breaths. Hiccups are another still-mysterious breath-related phenomenon.

Specialized centers in the brainstem automatically regulate the rate and depth of breathing depending on the body’s needs at any time. When carbon dioxide levels increase in the blood, it reacts with the water in blood, producing carbonic acid. The drop in the blood's pH will then cause the medulla (signalling centre in brain) to send nerve impulses to the diaphragm and the intercostal muscles, increasing the rate of breathing. While exercising, the level of carbon dioxide in the blood increases due to increased cellular respiration by the muscles, and so breathing rate increases. During rest, the level of carbon dioxide is lower, so breathing rate is lower.This ensures an appropriate amount of oxygen is delivered to the muscles and other organs. This automatic control of respiration can be impaired in premature babies, some drugs and other disease processes.

It is not possible for a healthy person to voluntarily stop breathing. If we do not inhale, and the level of carbon dioxide builds up in our blood, the urge to breathe generally becomes overwhelming. This irrepressible reflex is not surprising given that without breathing the bodies internal oxygen levels drop dangerously low within minutes leading to permanent brain damage and then death.

Adapted from the Wikipedia article "Control of Breathing", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki