While you’re reading this, hold your breath. What is now happening is your blood is delivering the last of oxygenated blood cells to your tissues while carbon dioxide is rapidly building up (hypercapnia). At the same time, there is a steady decrease of blood oxygen (hypoxia). The pH of your blood is getting slightly lower (acidic), and your heart starts to beat faster. God designed your brain to sense the increased carbon dioxide levels and initiates the effort for you to breathe. This will...