The nagging need to breathe is activated from a cluster of neurons called the central chemoreceptors, located at the base of the brain stem.
When we’re breathing too slowly and carbon dioxide levels rise, the central chemoreceptors monitor these changes and send alarm signals to the brain, telling our lungs to breathe faster and more deeply. When we’re breathing too quickly, these chemoreceptors direct the body to breathe more slowly to increase carbon dioxide levels. This is how our bodies determine how fast and often we breathe, not by the amount of oxygen, but by the level of carbon dioxide.
Chemoreception is one of the most fundamental functions of life. When the first aerobic life forms evolved two and a half billion years ago, they had to sense carbon dioxide to avoid it. [...] As humans evolved, our chemoreception became more plastic, meaning it could flex and shift with changing environments. It’s this ability to adapt to different levels of carbon dioxide and oxygen that helped humans colonize altitudes 800 feet below and 16,000 feet above sea level.













