AIR FORCE ACADEMY, Colo. — San Francisco 49ers tight end George Kittle played an NFL game at a significant height above sea level.
Kittle’s only one-mile ride came on September 25, when the Niners played for the Denver Broncos. His memory of how the altitude in Denver – 5,195 feet – had affected him was “slightly gasping,” but he also noted that he was still returning to football form from a groin injury.
As the Niners prepared to travel to Mexico City – at an altitude of 2,503 feet – for a Monday Night Football match with the Arizona Cardinals at Estadio Azteca (20:15 PM ET, ESPN/ESPN+/ABC), Kittle did what she always does. He has a question: He called Kansas City Chiefs hardcore Travis Kelce for advice.
Kelce plays annual games in Denver and threw for 92 yards and a touchdown against the Los Angeles Chargers, who they played in Mexico City in 2019.
“He said the altitude was tough,” Kittle said. “He also plays for Denver every year and so he said it’s definitely a big change from what they’ve played before… I know it’s going to be something.”
Kittle wasn’t the only 49er who expected height to be a challenge. In fact, as soon as the NFL announced the Mexico City game in the spring, the 49ers performance team, led by player health and performance president Ben Peterson, began looking for options to mitigate the effects of altitude.
Ten NFL games were played in Mexico City, four of which were during the regular season. The teams that preceded the Niners and Cardinals adhered to two schools of thought when it came to altitude adaptation: start as early as possible or as late as possible.
In some ways, Monday night’s game will be as much a battle of scientific philosophies as it is football.
On Peterson’s advice, the Niners chose the early route and arrived in Colorado on Tuesday to train and acclimatize at the United States Air Force Academy on Thursdays, Fridays, and Saturdays — at an altitude of 6,621 feet in the football stadium.
The 49ers will head to Mexico City on Sunday afternoon, hoping their time in Colorado will give them an edge.
“You want to practice at that height because the more days you spend in it, the more your body gets used to it,” Shanahan said. “Hopefully it makes Monday night easier for us.”
The Cardinals chose the other approach, as strength and conditioning coach Buddy Morris decided on a modified program that included stationary bikes and height masks that the Cardinals could use in their training facility. They will arrive in Mexico City on Saturday.
“We felt the program we could set up here for all the altitude training was really good and wouldn’t break our routine,” said Cardinals coach Kliff Kingsbury. “They’ve been working on this for the last two or three weeks. All of our guys are trying to prepare for it, but I know it will be difficult either way, whether you do it or not.”
However, acclimatizing to altitude is not as simple as spending time at higher altitudes.
It takes about three weeks to fully adjust to altitude, according to Inigo San Millan, a research associate in the department of Physiology and Nutrition and medical school at the University of Colorado in Colorado Springs. That doesn’t mean the 49ers can’t take advantage by spending the week in Colorado before Mexico City.
“Not enough time to fully adapt to height,” San Millan said. “At least enough time to avoid exposure to the effects of altitude.”
According to San Millan, even half getting used to it can only be possible if the 49ers take the right steps. He has worked with many athletes for 27 years, including Olympic medalists and Tour De France winners, while studying the effects of height on athletic performance.
As San Millan explains, the acclimation problem is not related to the amount of oxygen in the air. The main problem comes from barometric pressure.
Under normal conditions at sea level, the weight of the atmosphere can help push oxygen into the blood circulation that feeds the muscles. In a place like Mexico City, the barometric pressure is lower, resulting in lower oxygen saturation.
Athletes may have difficulty breathing at heights due to reduced oxygen levels in the bloodstream. In their research, San Millan and others believe that for every 1,000 feet above sea level, a person loses 2% of their ability to use oxygen, and the time it takes to feel tired is roughly 4% faster.
This means that in Mexico City, Niners and Cardinals can consume about 14% less oxygen than at sea level and reach fatigue about 28% faster.
There are built-in adaptations in the body to help in the form of increased amounts of red blood cells, which San Millan calls “oxygen taxiing,” so that there are enough of them to deliver the right amount of oxygen to the necessary tissues in the body. body.
However, the key to keeping Niners working is not to push too hard in that one week. Overtraining is typical for athletes trying to adapt to altitude, but they actually have to spend the first week doing very little physical activity, San Millan said.
Shanahan said on Monday that the Niners won’t be making major changes to their training patterns, but they didn’t train until Thursday, despite arriving in Colorado on Tuesday.
“There’s a double-edged sword to go for such a short time,” San Millan said. “Within a week you can adapt to some extent. But when you look at the possible side effects, you’ll see players not sleeping well, maybe not recovering well. It’s changed significantly.”
Beyond the training regimen, two other important factors for altitude adaptation are sleep and nutrition.
San Millan says that when working with athletes, she follows a first-week modified eating plan that includes adding about 30% more carbohydrates and protein to their diets to maintain energy levels.
The challenge for the Niners is not only getting them to do them right, but also managing a large number of players. While San Millan can monitor four or five athletes at once by performing blood analysis every five to seven days, the task is more difficult for a 53-man squad.
On sleep and nutrition, Kittle said there is a humidifier in every room at the team hotel The Broadmoor to keep the air moist, with an emphasis on drinking plenty of water and eating “as much as you can.”
Brandon Aiyuk said on Thursday that this week the Niners got a feel for how the speed of a soccer ball could increase in less dense air.
Feedback from players this week was that the altitude on the training ground wasn’t “too bad”, but this was most felt during “lined up games”, meaning long rides on either side on Monday can be tough to tackle.
Niners seem happy with their decision to taste the altitude in Colorado, even when paired with cold weather and snow.
“It’s good that we’re doing this here now, so it’s not a shock when we get to Monday,” said defender Fred Warner.