a sport in my opinion should involve testing mind, body and spirit, chess is an excelent game, test your mind and game knowledge, opening, mid-game etc. You can test your spirit/will in not giving up when you are losing a match, but doesnt involve any kind of physical exercise :/
Chess as a sport...
Do you consider variants of chess such as Backgammon to be sports as well?
.... backgammon based on complete luck factor like Ludo & other dice games...
At least we have not used dice in Chess yet..!!
Chess is totally based on ur mental strength, dedication & perfection...
Comparing backgammon with Chess is like.... comparison between Hollywood & Cartoon network..

chess boxing is a popular thing now. people box and between every round they move a chess board in the middle of the ring and they play a move. then go back to boxing
Chess players have a unique ability of taking in a lot of information and remembering relevant bits. So, memory and mental stamina are the key attributes.