Insulin reduces the amount of glucose in the blood by binding to insulin receptors embedded in the cell membrane of various insulin-responsive tissues like muscle cells and adipose tissue.
So when you start to exhale CO2 faster than your cells release it, its concentration in your blood drops. And with less carbonic acid around, your blood's pH starts to rise.
We are in a safe environment, so it is all right to reduce heart rate and blood pressure; we have more even and relaxed breathing; we reduce blood flow to the brain and just … chill.