[nsouth]

The key word is spontaneous breath retention. Google "kevala kumbhaka". Not BS at all, in fact it is a primary aim of the breathing exercises known as pranayama and is very widely documented within yogic texts, both old and current.

[djtriptych]

While breath retention is part of pranayama techniques, they are NOT beginner techniques, and misuse certainly does have the capacity to do damage.

Consider the inner breath as a pneumatic tool. Can you imagine holding in a powerful sneeze or cough and hurting yourself? That’s the power of the diaphragm. Getting it under control cannot be done overnight, and retention techniques increase the risk of accidental injury.