Costal Breathing (Chest Respiration)

呼吸には，大きく，胸式呼吸と腹式呼吸がある。幼児を除く現代人にとっての自然な呼吸は胸式呼吸であり，息を吸う際には胸（胴体の上部）を膨らませる（肋骨を開く）ので腹が凹み，息を吐く際にはその凹んだ腹が元に戻る。日本においてラジオ体操や学校で指導されるいわゆる”深呼吸”は，大きく胸を開いて空気をできるだけ多く吸い込むようにする胸式呼吸である。ここでは，息を吸うことに重点が置かれている。

Breathing is roughly classified into two groups; costal and abdominal. Natural breathing for people of today except infants is costal breathing (chest respiration), in which the abdomen becomes hollow in inhaling since that the chest (the upper part of the body) swells as the ribs are stretched or expanded, while the hollow abdomen returns to be as before (the abdomen swells) in exhaling. The "deep breathing" learned in school or Radio Exercise in Japan is costal one, which requires us to inhale as much air as possible by swelling the chest widely. Here, it put a stress on the process of inhaling.