Altitude problem in Mexico City: Why the thin air could become a burden for England

"As a result, with thin air significantly less oxygen is spontaneously taken up into the blood," Krüll tells the Deutsche Presse-Agentur. The body must therefore compensate: "That means, for example, it produces more oxygen carriers." A real acclimatization to the altitude, however, takes time. "But that takes about two to six weeks," explains Krüll. Those who live at high altitude long-term can produce enough red blood cells to do all the things that are taken for granted at sea level. The English team does not have that time.

Acclimatization takes weeks

The Three Lions have set up their training camp during the tournament in Kansas City in the U.S. state of Missouri, which sits at only around 280 meters. Their World Cup preparation also initially took place in West Palm Beach in Florida — four meters above sea level. "Between the matches against Congo and Mexico there are three days, and we can't adjust to it," Krüll describes the difficult starting position. "This is the most physically challenging place I have ever played football," a former professional told the BBC after a previous appearance at the stadium.

"The body is only ever as performant as it is able to take up oxygen," explains Krüll. "They will probably fall short on their running output, run out of breath earlier than they are used to at lower altitudes," the physician predicts. Specifically, he advises: "Harry Kane should therefore not, as before, wait until the 70th minute, but simply score his two goals in the first half — that would already be good for the English." Musculature no longer works oxygen-neutrally at high altitude. "That means the muscles don't work cleanly, but rather quickly go into oxygen debt," Krüll elaborates. In this process, sugar as an energy source is not fully broken down, and breakdown products — above all lactic acid — accumulate more quickly.

Advice from sports physicians

Thomas Tuchel views the situation soberly. "It is simply a disadvantage that we have to deal with," the English coach said after reaching the Round of 16 with a 2:1 victory over the Democratic Republic of Congo, thanks to a Kane brace. English sports physician Barney Wainwright of Leeds Beckett University recommends slowing the tempo of the game: "The 'Three Lions' should perhaps slow the game tempo a little, to give the players time to recover between phases of high-intensity play," Wainwright said. Tuchel adds: "You have to think very carefully about the moments in which you give everything."

The match has a special historical note. England has already played at the Azteca Stadium against Mexico and experienced a 1:2 defeat there in 1986 in the quarterfinals against Argentina with Diego Maradona's "Hand of God" goal and his goal of the century. In 2015, a former professional with Montréal Impact had to play the first leg of the Concacaf Champions League final at the Azteca Stadium — the match ended 1:1. The English team will travel by plane over some 2,250 kilometers from their training camp.

Little time until kickoff

The biggest problem is the little time until the Round of 16 in the German early hours of Monday at 02:00 CEST. The broadcast runs on MagentaTV. According to experts, there is hardly any time for medical altitude acclimatization, because the window between the group stage and the knockout round is too short.

Krüll summarizes the sports-medical side: "The body is only ever as performant as it is able to take up oxygen." If the limit is exceeded, performance drops set in quickly. "You have to think very carefully about the moments in which you give everything," Tuchel repeats his motto.

In the end, tactics, cleverness, and experience will determine whether England reaches the next round despite the altitude disadvantage. The starting position is unusual, but not hopeless — provided the team paces its energy correctly and takes its chances early.