Everybody is doing Buteyko — slow breathing, Papworth, pranayama and the measurement nobody takes

The fourth paper of the series After Buteyko, following No. 3, Stand up and lose your breath; the series begins with No. 1, The invisible breath. On the night of 7 October 1952, by his own account, Buteyko began to breathe less on a hospital shift, and his headache, chest pain and kidney pain went within a minute. Everything he built rests on that night, and the whole field has since reproduced it under other names. The paper sets Papworth, resonance-frequency breathing, cyclic sighing, paced slow breathing and pranayama side by side: the words differ, the results point the same way, and none of these schools measures volume, carbon dioxide and posture together. Paced at six breaths a minute without further instruction, volunteers lowered their end-tidal carbon dioxide by 5.2 mmHg, and by 2.7 when told to avoid deep breaths (Szulczewski 2019); the instruction that halves the fall is Buteyko's sentence. The paper names the standard instruments that would show the mechanics, sets out why Buteyko serves as the reference while his claims are left aside, and keeps the history of breathing apart from its clinic.