A level of fitness oriented for a specific heart beat rate range throughout a specific exercice. To prepare to one thing has zero to do with preparing to another. I assure you Nick does not rely solely in his triathlon training to go in the octagon, thus the comparison is up.
Just admit it was a real dumb comparison. One has to do a lot with cardio (evident when Diaz has some of the best if not the best cardio in MMA). And Math problems? I mean it was a terrible comparision.
No one here said he solely relies on triathlons.