That’s something I was concerned about when developing the game, tbh – that the breathing rate would be wrong for someone to an extent that it makes them ill, especially if their breathing entrains to the breathing animation continuing after the explicit prompting has passed. (Which is an intended effect.)
In general, do you find yourself to run out of breath easily? Alternatively, do you have extraordinary cardiovascular endurance? I’m not sure if my implementation is more at risk for producing hyperventilation (in people who start taking very deep breaths) or hypoventilation (in people with restricted breathing, higher oxygen needs, or habitually shallow breathing).