England meet host nation Mexico at the famous Azteca Stadium in the World Cup round of 16, and the big talking point before kickoff is the altitude.
The Azteca Stadium in Mexico City sits more than 2,200 meters above sea level. That is high, and the air up there has less oxygen, which makes running and breathing harder. England are based near Kansas City at only about 280 meters, so they have not been training in thin air. Their coach Thomas Tuchel said it is impossible to fully get used to the altitude in just a few days. He told reporters that the usual advice is to arrive ten days early, but his team simply cannot do that. So England will fly in one day earlier than normal and hope for the best.
A doctor who works with marathon runners in Berlin, Dr. Matthias Krüll, gave England a simple tip: score early, then manage the game. He said the team will probably run less total distance than usual and get tired faster if the match goes long. Quick goals take pressure off your legs and your lungs, he explained. Mexico, meanwhile, have won all four of their games so far and have not conceded a single goal. They will play in front of their own fans, and a million or more supporters may gather on the main avenue in Mexico City to watch on big screens.