too high co2 can cause shortness of breath symptoms. happened to me earlier this week. i was drinking too much sparkling water, taking b1 hcl orally, aspirin, t3. i ending up waking in the middle of my sleep but when i wanted to go back to sleep i felt like i would suffocate in my sleep from not breathing. it was scary as fuck. i stopped everything and just drank a shit ton of coconut water and sunbathing, some cyproheptadine to relax. now its gone.
check out this post
https://lowtoxinforum.com/threads/what-is-happening-in-a-panic-attack.16579/#post-225622
"CO2 seems to be a culprit here for some people. But it's not as simple as high CO2 = panic, since bag breathing works.
That lead me to the following SA article from 2010 explains the mechanism is high acid levels in the amygdala is responsible for the fear response (demonstrated by mice with KO genes). They say CO2 increases acid levels in the the brain and most patients with a panic disorder who breathe in air with 35% CO2 (air is typically 0.04%) experience a panic attack while healthy volunteers do not. Close relatives of the people who experience panic attacks will also usually have a first time panic attack when they breathe in the high CO2 air suggesting a genetic connection. Lactate buildup also increases brain acid levels and exercise is said to make brain lactate removal more efficient, which is in line with exercises anti-anxiety effects.
Panic Attacks as a Problem of pH"