What really drives us to breathe? And how dangerous is it to hyperventilate and hold your breath? It has a lot of names: hypoxic drive, respiration, breathing... needless to say, you know what it is. But have you ever thought about it? I mean not in the way that you're thinking about breathing now. HA. Deal with that. But have you thought about how your body does this when you're asleep, when you're distracted or really focused. No matter what you're doing (for the most part) your body is breathing for you. That drive to breathe is strong. The reason you can do it without thinking is because your brainstem is doing the work and making the decisions. Breathing is a really complex balance of pulling oxygen in from the environment, and getting carbon dioxide out of your blood. Even though we need oxygen to survive, the main influencer of the drive to breathe isn't oxygen, but CO2 -- or really, CO2's tendency to dissolve into water. The more CO2 there is in your blood, the more acidic it is. The brain doesn't like blood that's too acidic or too basic, so it needs to monitor it constantly. That's why, spread throughout your body are chemoreceptors. Central chemoreceptors are in your brain, peripheral chemoreceptors are in the body's blood vessels - all over the place. Those receptors sense subtle shifts in the levels of carbon dioxide and the acidity of your blood, and send that info to the respiratory centers in the medulla of your brain stem. Based on the acidity readings from those chemoreceptors, your brain directs your lungs to make little adjustments in your rate of breathing to try and keep your CO2 levels as steady as possible. It happens all the time. Source
