A couple of minutes into his first morning run, Frankie Edgar felt it.
The altitude. The reason he went to Denver two weeks ahead of his fight instead of the usual five days earlier.
Latest MMA stories
"The first four-hundred meters I felt it a little bit," said Edgar, the former UFC lightweight champion. "Then I settled in and then ripped the rest of the run."
Edgar has been in the Mile High City since July 28 preparing to face current lightweight champion Ben Henderson on Saturday at UFC 150. Henderson presents enough challenges on his own, but going five rounds against a fighter in a city that has 17 percent less oxygen in its air than cities at or close to sea level? That's worth a few extra hotel room nights.
By comparison, Edgar's hometown of Toms River, N.J., is 40 feet above sea level. The elevation, something that many NFL, NBA, MLB and NHL players deal with each season, doesn't necessarily concern Edgar, he said. Rather, he is just "making sure I do everything right," when it comes to getting his belt back.
"If you let your mind run away with it, you can definitely feel it a lot more than it really does affect you," said Edgar (14-2-1, 9-2-1 UFC). "Mind is definitely tougher than the body."
Edgar's toughness is never in question. He fights in the 155-pound weight division and barely cuts much weight leading into the fight, while his competition will drop significant pounds to make the limit the day before the fight. By the time the fight actually goes off 24-plus hours later, Edgar's opponents are closer to their normal "walking-around" weight. In the case of Henderson, that could mean 170 to 175 pounds.
Edgar vs. Henderson is a rematch, of course. That's what Edgar goes. He fights a guy, then fights him again. He took the title - convincingly - from B.J. Penn in April 2010, then defended it against him four months later with the same result. He fought Gray Maynard to a draw on New Year's Day 2011, then beat him in the rematch in October. Henderson (16-2, 4-0) defeated Edgar by unanimous decision last February, winning 11 of the 15 rounds on the judges' score cards.
That's 28 months, six fights, three different opponents.
"Frankie's a tough fighter and we all know he's a lot better in rematches," Henderson said. "It's one of his biggest things. His coaches are great and they always put together a great game plan for rematches and finding weaknesses and holes in their previous opponent."
It's a scenario that brings positives and negatives. Edgar has enough experience with immediate rematches to know both sides.
"There's no better way to get a real feel for a guy than getting in there with him and throwing down," Edgar said. "The negativity of it is that you have to think about this guy for another whole camp. And he also gotto see what you brought to the table the last fight."