Starting from the 1960's, yoga books and nearly all yoga teachers started to promote the deep-breathing myth: one should breathe more air (even at rest) and expel "toxic" CO2. However, hundreds of clinical studies showed and proved that hyperventilation reduces oxygen levels in cells, while CO2 is crucial for health. Deep breathing, as during pranayama, only looks deep. In reality, as ancient yoga texts teach, pranayama should be done with...