Board Thread:Role Play Discussion/@comment-5290299-20140502223634/@comment-13488655-20140607055020

Not all the time.

And as a few more examples, Blackbeard used to place himself and a number of his men in a room full of fumes from burning sulphur (Making low amounts of oxygen) for fun, There are people who live in high mountains with low oxygen levels and have adapted to it.

Human can adapt to numerous environments and situations. If you still don't believe, go onto google and look it up.