Well people will debate about this for eternity, but the fact is that poker is a competitive game and not a sport. That's not an opinion.
Sport - an athletic activity
requiring skill or physical prowess and often of a competitive nature (http://dictionary.reference.com/browse/nature), as racing, baseball, tennis, golf, bowling, wrestling, boxing, hunting, fishing, etc.
While poker does require skill, along with mental stamina, and exercise may improve mental acuity (you can technically train for it) there is nothing, even remotely, athletic about competing when playing poker in the slightest. Sadly, fishing is more of a sport .
If poker is a sport, then professional poker players are athletes. Now that's some funny ****.
Chick: So, what do you do?
Leather ass: I'm an athlete.
Chick: Omg really, what sport?!
Leather ass: Poker.
*end blind date*