Breathing with the diaphragm or diaphragmatic breathing is one of the set of techniques you can use to quiet your negative self talk or what Timothy Gallwey calls our down putting "Self 1".
Here’s how to breathe with the diaphragm
Breathe in through your nose while gently pushing out your abdomen. You should be able to feel your abdomen moving outward.
Breathe out slowly through your nose while gently pulling your abdomen inward to empty your lungs.
Breathing with the diaphragm is known by various names such as diaphragmatic breathing, deep breathing, conscious breathing, stomach breathing, belly breathing, abdominal breathing and rhythmic breathing. The US Green Berets elite force calls it "combat breathing" and "tactical breathing".
When we were newborns, we naturally breathe with our diaphragm but most of us lose this as we grow up.
As we grow up we resort to shorter, rapid, shallower breathing with the chest which is more like gasping and panting.
Breathing with the diaphragm has both mental and physical benefits.
After years of shallow panting, deeper breaths seem unnatural and feel awkward. Deep baby breaths now need conscious effort. And here is the thing - this conscious effort, takes our minds away from the negative self talk that is chattering in the background at the moment of truth.
When we breathe with our diaphragm, our breathing rate is slower. And with this, our heart rate, and blood pressure also goes down. We automatically calm down.