CO2 Threshold and Sleep Apnea

Did you know that if your carbon dioxide levels drop just a fraction too low during sleep,

your brain will simply stop telling you to breathe? During sleep, carbon dioxide—or

CO2—becomes the dominant driver of your breathing. Scientists have identified a critical

level known as the apnea threshold. In stable sleep, your CO2 levels are typically higher

than when you’re awake, but if they fall just 2 to 6 millimetres of mercury below

that sleeping level, your respiratory rhythm ceases. This narrow safety margin is called

your "CO2 reserve". If a brief arousal causes you to breathe too heavily and blow off too much

CO2, you can actually cross this threshold, leading to a cycle of stopping and