BEA 71 I suspect experienced shortness of breath, even though he didn't say that directly. BEA 71 - Please correct me if I am wrong.
The link you posted David said this towards the end....
Dr. Campos explains, “Dyspnea, the feeling of shortness of breath felt with masks by some, is not synonymous [with] alterations in gas exchange. It likely occurs from restriction of air flow with the mask in particular when higher ventilation is needed on exertion.”
So your Vol O2/CO2 may not vary significantally but you can experience shortness of breath... And that can be distressing/frightening.
Last edited by Compton3fox; 18th Nov 2021 at 21:19.
Reason: Correct a typo