Every time I spend time with a group doing breathing assessments, this question comes up.
And I can understand the problem, as deep breathing is rooted in our psyche as healthy breathing that gets more oxygen to the brain.
But anyone who teaches breathing should understand THE BOHR EFFECT
Which mean that in the body, if there is
A low CO2 in the blood, as deep breathing has blown off too much of it out of the lungs, the body becomes a bit alkaline.
This strengthens the bond between the haemoglobin and the 4 oxygen molecules each one carries and oxygen is not released as easily to the tissues in the body that need it.
E.g. people who hyperventilate (breathe too much air in and out by light fast or slow large breathing, or sighing and yawning too often) – often feel a bit dizzy or spacey as their brain is not getting all the oxygen it wants.
But in active working muscles where there is a raised CO2, it is a slightly acid situation that weakens the bonds between oxygen and haemoglobin and oxygen is released easily.
I like this Youtube video that shows the Haemoglobin like a car with 4 wheels like the 4 oxygen molecules.
So gentle nose-diaphragm breathing delivers the best oxygen to the body at rest. It ‘loosens the nuts holding the wheels on’ the haemoglobin car – less breathing effort for more oxygen to the brain.