Toughest venues: Altitude adjustment

5. Sports Authority Field at Mile High, Denver Broncos

Denver has the NFL's best home winning percentage going back 30 years, at .700.

The Mile High thing is no myth. The Broncos seem to enjoy pointing this out.

A sign above the visiting locker room entrance reads: "ELEVATION 5,280 FEET ABOVE SEA LEVEL."

Denver cornerback Champ Bailey noticed it when he played his first game there, in 2001 as a member of the Redskins.

"Oh, yeah," Bailey said. "In an up-tempo game, the altitude wears you out. Nobody coming in here is used to it."

The human body performs at maximum efficiency in sea-level air, where the concentration of oxygen is 20.9 percent and fully saturates the hemoglobin in the blood. The higher you climb, the lower that number gets.

"It's real," insisted former Patriots linebacker Tedy Bruschi. "It affects you. The oxygen you're breathing into your muscles isn't the same. You feel yourself gasping."

In the Broncos' home opener against the Steelers on Sept. 9, Ben Roethlisberger's 3-yard pass to Mike Wallace gave Pittsburgh a 19-14 fourth-quarter lead. And then Peyton Manning orchestrated no-huddle drives of 10 and 12 plays, and the Broncos went on to score 17 unanswered points.

"You could see the fatigue," Bailey said of the Steelers. "Peyton has really opened up our offense. If we're in a shootout, it definitely works in our favor."

In Week 4, the Raiders and Broncos each produced two first-half scores -- and then Denver outscored Oakland 27-0 in the second half.

The professional teams in Denver all play to the altitude. The Nuggets play an up-tempo, helter-skelter brand of basketball designed to leave you gassed by the fourth quarter. The Avalanche have typically utilized small, fast defensemen, while the Colorado Rockies search for hitters who can power home runs through the thin air.

The Broncos? Quarterback John Elway won a pair of Super Bowls and carved out a Hall of Fame career by no-huddling defenses to death in the fourth quarter. As the Broncos' executive vice president of football operations, his sense of nostalgia played a large hand in bringing Manning to the team.

The original Mile High, built on a former landfill, began its life as Bears Stadium in 1948. Nearly four decades ago, it was Jim Saccomano's place of work as the public relations/public address announcer for the Triple-A Bears baseball franchise. He measured from the fence to the 20th row, 30th and so on so he could reliably announce the distance his team's home runs traveled.

"Usually, 400 feet is a good shot, but we hit a lot of taters," Saccomano remembered. "With the thin air, 460 feet, 480 was routine."

Today, Saccomano is the Broncos' vice president of corporate communications, in his 35th season with the franchise. He is an astounding wealth of information. Did you know:

• Two of the four longest field goals in NFL history came at Mile High. Jason Elam (1998) and Sebastian Janikowski (2011) both connected on kicks from 63 yards. Unlike David Akers' 63-yard field goal for the 49ers in Week 1, their stout kicks did not bounce off the cross bar before going through the uprights.

• The longest punt in NFL history belongs to the Jets' Steve O'Neal, who uncorked one 98 yards, yes, at Mile High in 1969. The ball traveled approximately 75 yards through the thin air.

• Since the merger in 1970, only one team -- the Steelers -- has more home wins than the Broncos' 223.

• And, going back to that first victory at Mile High -- against Pittsburgh, of all teams -- the Broncos have sold out 343 consecutive games. That's 43 years and counting.

Saccomano wants you to know that Elway and Manning have played for only 17 of those seasons.

"Not even half," Saccomano said. "It's got to be the building!"

Carl Peterson, the Chiefs' longtime general manager, grew regrettably intimate with Mile High since his team had to play its AFC West rival there on an annual basis.

"They had those steel stands and the people would stamp their feet," Peterson said. "It was literally shaky up there. When they got going, I thought the press box was going to come down."

The modern version of Mile High was christened in 2001. For the cool fee of $120 million for 10 years, it was called Invesco Field at Mile High. Last year, Sports Authority signed a 25-year naming deal worth $150 million.

It was probably money well-spent.

Bailey remembers details from his first game at Mile High with frightening clarity.

"The game started in sunshine, then it rained," Bailey said. "Then it turned to sleet, then snow. It was a crazy experience. You don't get extreme weather like that anywhere but Denver. I remember it was sunny at the end, too."

Maybe that was because Bailey and Washington managed to win, 17-10. The Redskins and Broncos each fumbled the ball six times, and then-Broncos coach Mike Shanahan called it the worst offensive performance he had ever seen in the NFL.

Now, all of those home-field factors are working in Bailey's favor.

"It is a tremendous psychological advantage," he said. "People come in thinking about the weather, the altitude. If you're worried about something, it really weighs on you. At Mile High, people psych themselves out."

NFL Hot Read: Toughest venues

No. 1: Scoreboard, baby | No. 2 Feel the noise | No. 3 Frozen in time

No. 4: Strong as steel | No. 5: Altitude matters | No. 6: Tailgating haven