It also bugged me that I can hold my breath way longer than my character and I've never taken on 1000 super mutants and ran across 3 counties in a day. --- "Dokomademo...agaite yaru..!" "No matter how far...I will fight it..!"
http://fallout3nexus.com/downloads/file.php?id=1409 This mod has the perk you are looking for. I think its called fishboy/fishgirl in the list of perks. I have this mod but havent tried that perk yet. --- People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. -George Orwell Semper Fi