My guess is that the benefits of the 30-60 minutes 3-6x a week you spend in the gym far outweigh any of the negatives of elevated CO2 exposure. You know when a

My guess is that the benefits of the 30-60 minutes 3-6x a week you spend in the gym far outweigh any of the negatives of elevated CO2 exposure. You know when a gym has poor ventilation which means that's not a gym you want to be at.