The Broncos had spent the first half chasing the Packers around Empower Field at Mile High. Green Bay put together four scoring drives of eight, 10, nine and eight plays, and Denver found itself trailing 23-14 early in the second half, with its 10-game winning streak in jeopardy of coming to a whimpering end at home.
But during a timeout midway through the third quarter, coach Sean Payton pointed across the field toward Green Bay’s sideline.
“Look at them. They’re tired. You got ’em,” wide receiver Troy Franklin remembers Payton saying.
Denver scored 20 points to Green Bay’s 3 the rest of the way, winning 34-26. Inside the Broncos’ locker room, there’s an inherent belief that once the fourth quarter hits, their roster holds a biological advantage over their opponents. They say they’re used to playing at 5,280 feet above sea level. Other teams aren’t.
“We usually can tell when we got them. We look across and see them tired,” cornerback Ja’Quan McMillian told The Denver Post.
Real science or urban legend?
But while the Broncos’ belief in the altitude edge is steadfast, its impact appears to be diminishing. The data shows Denver’s home advantage is shrinking. As NFL teams have become more sophisticated in sports science, several experts told The Denver Post that altitude is less of an advantage for the franchise than it once was.
Ever since the Broncos moved into Mile High Stadium in 1960, the franchise has broadcast its stadium’s elevation as part of its identity. It shows up in the altitude-focused video montages that play on the Jumbotron, in the sign outside the opposing locker room that reads “Elev 5280′ Altitude Sickness is Real,” and in the messaging that comes from Denver’s coaching staff.
First thing teams see when they pull into Mile High
— Tracy Wolfson (@tracywolfson)
The players certainly believe in the edge. Defensive tackle Eyioma Uwazurike said he “almost died” during his first workout in the altitude four years ago and now watches opponents labor through it on Sundays. He estimated that it takes a player’s body 5 extra seconds to fully recover from a play at altitude compared to near sea level. In the second half, the elevation starts to wear on teams, he said.
“You can see them feeling it,” Uwazurike said.
Since 2001, away teams have averaged 6.07 points in the fourth quarter at every other stadium and 5.61 points in Denver, according to Kristopher Pruitt, a professor at the University of Colorado and expert on mathematical modeling in sports. And while that’s still well within the standard margin of error, that difference could be the difference in a game’s outcome.
Wide receiver Jaylen Waddle, who arrived in Denver this offseason from Miami — a city that sits only 6 feet above sea level — said he thought the altitude’s impact was a “myth.” After his first few workouts, though, Waddle felt his body being affected and now says the altitude change was “definitely real.” Tight end Evan Engram said he needed to come off the field several times to get his breath back through an oxygen mask when he played in Denver as a member of the New York Giants.
Marc Lewis, a former director of applied sports science for the Houston Texans, said nearly every athlete experiences the same effects when they first step into higher altitude. Because there is less oxygen available to the body, athletes either breathe faster or for longer, Lewis said. An athlete’s cardiac output also increases to pump more blood to active muscles. It takes a few weeks for most athletes to adjust to the high altitude of places like Denver, Lewis said.
“Everything’s going to be more physiologically costly to the team that’s visiting, that’s not acclimated to the altitude,” Lewis said.
But how much home-field advantage does the altitude actually give the Broncos? The data shows a more muddled story.
Since 2001, the Broncos have hosted 224 games. The average number of points scored by away teams in Denver is within one point of the average points scored by away teams at every other NFL stadium — a sample of more than 6,700 games – according to Pruitt. There was also no statistically significant difference in margin of victory between Denver and the rest of the league at home, Pruitt said.
“The urban legend suggests it’s a thing, but the data shows it’s not always that way,” Pruitt said.
Sports science trims altitude advantage
The of the Broncos’ home record dating to 1975 found a similar trend. From 1975-1988, between 67 to 72% of the teams’ wins in a season came at home. From 1999 to 2015, that figure dropped to around 60%. Over the last decade, it’s fallen to 55% — in line with the NFL average of 53% to 57%.
The Broncos do have the eighth-highest home winning percentage in the NFL since 2000, but that’s right in line with their overall winning percentage — which is the seventh-best in the league during that same frame.
Those numbers follow the league’s broader trend of home-field advantage. From the 1970s through the early 2010s, home teams won contests close to 60% of the time. Since 2019, the win rate for home teams has sat around 52%. 2024 was the fourth time in six years that NFL home teams won 53% or fewer of their games. There were just four such seasons in the previous 50 years, according to .
So what’s changed? There are a variety of factors that have played into the reduction of home-field advantage, but Lewis and Pruitt said teams’ awareness of sports science could play a role in Denver. The Broncos revamped their entire sports science department two years ago, according to a source familiar with the department. The staff is led by director of sports science Joseph Danos and assistant sport scientist Bailey Speight. The Broncos declined to make Danos or Speight available for an interview.
In Houston, Lewis had two other full-time sports scientists under him, eight strength coaches and four dietitians. The Cleveland Browns build an altitude simulation room. Before the AFC Divisional game last year in Denver, Bills players wore altitude training masks while running on a treadmill and used a low-oxygen-stimulating chamber to try to acclimate before the game, .
Dr. Randy Wilber, a senior sports physiologist at the U.S. Olympic Committee, told The Post that he believes NFL teams have made a strong commitment to using science in their preparation for games in Denver and Mexico City. Wilber said trainers and sports medicine staffs have adopted the effective use of pre-acclimation/acclimatization strategies in the week leading into the game in Denver, including “intermittent hypoxic training” and “repeated sprint training in hypoxia.”
Pruitt also said football is a unique sport. Unlike soccer or other aerobic sports, where athletes are constantly running, football is essentially a game of full sprints and stops. Pruitt said he believes it takes most of the game for the accumulated effect of all those individual sprints to add up in a taxing way on the body.
“Whenever we play in some type of different altitude, or we travel time zones, there’s so much planning now. Performance teams in the NFL have changed drastically,” Lewis said. “The level of fitness of NFL players is a lot different that it was 20 or 30 years ago.”
“Because of how much teams put into it now, (Denver’s advantage at home from altitude) is more on the margins of performance … It’s less of a competitive advantage overall,” he added.
Mind games in tight games
But in a league where the most frequent margin of victory is 3 points, according to a , teams are constantly searching for minimal advantages. Before the biggest game at Empower Field at Mile High in almost a decade, Payton wanted to remind his team of an upper hand they had over their opponent. In the lead-up to the team’s playoff game against the Bills last year, the entire roster was handed a mini oxygen tank to keep with little notes scribbled onto it.
The message from the coaching staff was simple, Engram said: It was going to be an “oxygen tank” game. Denver wanted to play fast to tire the Bills out and take advantage of the stadium’s natural advantage. And while the messaging did not exactly hold up — the Bills ran 10 more plays than the Broncos and outscored them 20-13 in the second half/overtime — Denver still pulled out its first home playoff victory since 2015.
“When you get in playoff football, it’s going to come down to a play or two, situational football, how much can we strategize to use every possible advantage,” Lewis said.
That’s the physical side. What the altitude doesn’t account for is the mental gymnastics the Broncos try to put opponents through. The of opponents gasping for air, putting oxygen masks over their mouths, and leaning over in exhaustion. “A Mile-High home field advantage,” they call it. Every visiting team is greeted with a massive orange sign outside their locker room that reminds them of the elevation’s impact.
Lewis said research shows that psychological messaging can have a physical effect on a person’s body. The Broncos are creating a “continual reminder” of the elevation in every player’s mind, which could make them feel more tired or affected by the altitude than they actually are. Pruitt agreed.
“If I were an analyst for one of these other teams, I would make sure my players knew that there’s no difference in points scored. Like, you know (the Broncos) are gonna tell you all this stuff. They’re gonna play all these mind games, like putting mile high in the away team locker room,” Pruitt said. “It’s all over the place. The psychological warfare and trying to convince the other team that they’re gonna be affected by this.”
Bills quarterback Josh Allen said before the playoff game that the best thing to do is “not really talk about it, not really think about it, not really make it a problem.” Last year, the Patriots faced criticism for flying to Denver a day before the AFC Championship Game. Lewis said that was actually the right move, though, because any training in altitude is going to be more taxing on an athlete’s body.
“Honestly, I don’t think there is any prep that you can do,” Engram said.
The Broncos will host the Jaguars on Sunday. Jacksonville, which plays at an elevation of around 16 to 20 feet, was the only team to beat Denver at Empower Field last season.
So while the data doesn’t fully support the belief that is perpetuated throughout Denver’s locker room, perhaps the roster’s conviction in the altitude advantage is what matters most.
“It ain’t no myth. It’s real,” McMillian said.
