> I've heard some people can (train themselves to?) tell when the CO2 level rises in the room. Has anyone here managed to? If so, do you have any tips on how (or whether!) to do this, and/or what it feels like (if it's possible to give any vague explanation in text)?
The best indication is feeling sleepy. Once you become sleepy go outside and take deep breaths, then you understand the sensation difference between O2 and CO2.
The best indication is feeling sleepy. Once you become sleepy go outside and take deep breaths, then you understand the sensation difference between O2 and CO2.