The Chairman
Chairman of the Board
Chemoreceptors in the brain are largely tied to CO2 and not oxygen. This is why we can go on %100 surface O2 and not feel weird. The more oxygen you metabolize, the more CO2 you produce. IOW, a build-up of CO2 is what causes you to want to take a breath... not the lack of O2. In fact, if your O2 is off on your rebreather, you'll probably never know unless you monitor it via working oxygen cells. You'll simply go to sleep, never to awake never knowing your O2 is so low that it won't support life.Heartrate is linked to oxygen consumption.