The article talks about the importance of avoiding a high blood acid level (the pH level) when you have diabetes. This condition is called metabolic acidosis. This must be caused by some kind of malfunction in the metabolic system.
The shallow breathing and then the deep slow breathing are ways that the body tries to correct this high acid level in the blood.
I've read a little about pH in the healthy person. It's supposed to be healthier to have a more alkaline rather than acidic blood and urine.