Jimmy Smith knew it was real the first time he walked up the big hill to football practice, his 18-year-old lungs unable to find enough air. In the years that followed, the images of husky linemen, gasping on the sidelines, only confirmed the potency of Colorado's thin, Rocky Mountain air.
The Ravens cornerback played at the University of Colorado in Boulder, which sits about a mile above sea level. That's almost exactly the same elevation he and his teammates will encounter at Denver's Sports Authority Field on Saturday when they try to keep their season alive in an AFC divisional-round playoff game against the top-seeded Broncos.
With Peyton Manning at quarterback, a wickedly fast defense and 11 straight wins under their belts, the Broncos are formidable enough without the climate affording them any extra advantage. But many players and analysts say the thin air gives them exactly that, literally stealing the breath from visiting opponents who have not had time to adjust.
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Sports Authority Field at Mile High, 1701 Bryant Street #700, Denver, CO 80204, USA
"I watched teams cave all the time from the altitude," Smith says. "It's just nothing you can really get used to."
Though it's hard to pinpoint altitude as the cause, the Broncos have been one of the league's best home teams for decades and have been almost unbeatable at home in the playoffs — 13-3 all-time.
"There are real physiological and therefore psychological advantages to the team that plays at altitude," says Randy Wilber, a senior physiologist at the U.S. Olympic Committee's lab in Colorado Springs and a longtime expert in high-elevation training. "If the talent on the field is equal, I'd put my money on the team that plays at altitude."
The Ravens have not played in Denver since 2006, and many of the team's players have never experienced a game a mile above sea level. "It's an advantage, obviously, for the Broncos," says Ravens coach John Harbaugh. "They live there. They play there. They practice there. No matter who goes out there and plays — playoff game or not — it's got to be an advantage for them. It has been over the years."
Based on consultations with team doctors, Harbaugh decided not to fly to Denver until Friday evening so players would spend only about 24 hours in the thin air. He says Ravens physicians have also dispensed health tips.
But the reality, says Smith, is that the Ravens can't do a whole lot to acclimatize themselves. They practice in Owings Mills, about 500 feet above sea level, which will never compare to Denver's 5,280 feet above sea level.
"There's nothing you can really do," Smith says. "You've just got to go in and tough it out. It takes about two weeks to get used to it, but we haven't got two weeks."
Altitude is a fascinating subject to broach with professional football players. Though it's a scientific certainty that the human body behaves differently at higher elevations than at sea level, these guys widely disagree on how big of a deal it is in the context of a game.
Ask Ravens safety Bernard Pollard, who has played at Denver four times in his career, and he'll tell you it's "going to be a problem." Linebacker Ray Lewis, who has also played four games there, says it's "not that big of an issue."
"It's very real," Pryce says. "Some people say it's psychosomatic, but I watched [former offensive lineman] Lincoln Kennedy almost pass out from it in the middle of a game. I was back in Denver recently and just walking up the steps, I couldn't breathe."
And Foxworth: "I didn't feel like it was real issue except that it felt like a psychological advantage. I never remember anything happening in the course of a game that I would attribute to the altitude."
Less oxygen the higher you go
The science of altitude performance is simple. The body takes in less oxygen at higher elevations, and it must produce more red blood cells to compensate. But that adjustment doesn't happen instantly. As Smith says, it takes up to two weeks. So when athletes land in Denver, they often experience quickened heart rates and some shortness of breath. It's all routine, unless you're trying to perform at an optimal physical level against guys who have played at altitude for months.
Wilber says the most common concerns for visiting teams are fatigue or breathlessness because of low oxygen saturation in the blood and dehydration because of the dry air. On the more extreme end, Pittsburgh Steelers safety Ryan Clark lost his spleen and gallbladder after having a bad reaction to the high altitude because he carries sickle cell trait, a genetic abnormality. Clark has sat out subsequent games in Denver, adding to the Broncos' home-field advantage against the Steelers.
On the plus side, Wilber says, players will be able to run faster and throw and kick the ball farther because of reduced air resistance. Of the four 63-yard field goals in NFL history, two were kicked in Denver as was the longest punt, a 98-yarder in 1969. Harbaugh has already talked about unleashing Justin Tucker to kick longer field goals against the Broncos.
Wilber says Baltimore's preparations should be fairly simple — supplemental tanks of pure oxygen on the sideline and plenty of fluids to battle dehydration. He says some teams also give players supplemental oxygen the night before the game. Others check hydration levels using pen-sized devices that analyze small urine samples.