I’ve had a Co2 monitor for years. I get headaches from increased Co2 levels plus the lethargic state. It’s been revolutionary - including on long drives where it’s def saved me from crashing.

Personal opinion, you can see cognitive decline at 1000 ppm. Not “ur a zombie” but it’s there. Airflow has vastly improved my life.

Another personal opinion - the coporate stupidity and inane behavior we all see tracks back in part to Co2 levels turning people into quasi zombies. It’s a lot easier to just not care, and things don’t click like they should, when in higher Co2 environments - pushing everyone to rote, process, unthinking approaches. Sounds familiar?