Nobody said hockey is easy, it's not. However, it is not more physically demanding that sports that require running and jumping. In fact, take out the rough stuff (cross-checking, boarding, fighting, etc) and hockey would probably slot in right under field hockey in terms of wear and tear.
Beach Volleyball produces greater wear-and-tear on the human body than Hockey.
Gordie Howe played in all 80 games in 1980 as a 52 year old.