Huh. Are you denying the upper safe level of serum bicarbonate? Just because we can tolerate 800 ppm of CO2 doesn't mean we can keep pushing it forever; there is clearly a limit. I suggest actually reading the paper.

Diving is not a 24x7 activity, and so it doesn't relate.

saturation diving IS a 24x7 activity, people often spend weeks in underwater pods. And the point I was trying to make is that the premise behind the paper doesn't hold up to scrutiny when indoors CO2 levels are already elevated like that.