Originally Posted by
billydonn
Worth noting: Lots of people riding in a room that isn't well ventilated can not only heat the room, it can lower the O2 level in the room. IMO it is also nicer when a spin class is led by someone who actually rides a bike. Anyway, good luck with it. Indoor riding can really be valuable and productive stuff.
You talkin' about methane?
... I know some people who seem able to "lower the O2 level" singlehandedly...