It has been proven that life could have survived, survived with greatness actually, with the oxygen (this is good ask any scientist) people could have ran forever and not tire.
Except for that pesky spontaneous combustion burning your running shoes off your feet....
Long before your time, PE, but what killed the three Apollo astronauts before they even launched the rocket back about 1970?
And don't ask
any scientist - I'm one, and I'll tell you AiG is utterly full of it.