 but  according to Joss Whedons canon, vampires do not breathe, or at  least, they do so only for effect. This "vampire fact" was shown in  Season 1, Episode 12, when Angel cannot perform CPR on Buffy, but  Xander can. Meanwhile, in Season 4, Spike fakes heavy breathing as  though he has been running, but its just a trick so that he can get  into Giless house.