> the human body can't directly detect blood oxygen levels, and only infers them from blood CO2 levels This is not quite accurate. The body monitors blood chem

> the human body can't directly detect blood oxygen levels, and only infers them from blood CO2 levels This is not quite accurate. The body monitors blood chemistry centrally (in the brain and spinal cord) and peripherally (in the blood vessels). Central chemoreceptors only monitor pH of the cerebrospinal fluid, which indirectly tracks blood CO2, but don't monitor O2. Peripheral chemoreceptors monitor O2, CO2, and pH. https://courses.lumenlearning.com/boundless-ap/chapter/respiration-control/ https://courses.lumenlearning.com/boundless-ap/chapter/respi...