In short: At 2,200 meters of altitude, the air has less available oxygen and the body loses more water just by breathing. Mexico City, one of the venues for the 2026 World Cup, turns altitude into an additional opponent. And that opponent is fought, above all, with hydration.
Playing soccer at altitude: why Mexico changes the game (and hydration)
Mexico City Stadium, the historic Azteca rebranded for the 2026 World Cup according to FIFA's sponsorship policy, is located at 2,200 meters above sea level. The entire city averages 2,240 meters. Guadalajara, another Mexican host city for the tournament, is somewhat lower at 1,566 meters, but is still high-altitude terrain for almost any national team on the planet. For teams arriving from sea-level cities, playing there is not just a change of scenery. It's a change in the rules of how their bodies get energy.
This is not new for 2026. Already in the 1970 and 1986 World Cups, both also in Mexico, coaching staff talked about altitude as a decisive factor. What has changed is that today, sports science explains quite precisely what exactly happens to the body, and why hydration is a central piece of that story.
Less oxygen, more work for the same effort
At 2,200 meters, atmospheric pressure is lower and each breath brings with it fewer oxygen molecules than at sea level. The heart and lungs compensate by working harder to transport the same oxygen that previously arrived with less effort. This is why anyone visiting Mexico City without acclimatizing notices that they climb a staircase and arrive more tired than expected. For a soccer player running at maximum intensity for ninety minutes, that same phenomenon is multiplied.
The physiology of altitude has been studied for decades in sports medicine (Bärtsch P, Saltin B, Scandinavian Journal of Medicine & Science in Sports, 2008), and one of its most consistent conclusions is that real acclimatization takes days, not hours. Teams that land 48 hours before the match do not give their bodies the time they would need to fully adapt. They play, literally, at a physiological disadvantage against an acclimatized opponent.
The lesser-known reason: altitude also dehydrates
Here's the part that is almost never told outside of sports medicine circles. Altitude not only reduces available oxygen. It also increases the body's water loss through two silent pathways. The first is respiratory: high-altitude air is drier, and each breath – and in a high-intensity soccer match there are thousands – carries more water vapor from the lungs than at sea level. The second is a natural body response called altitude diuresis, an early adjustment of blood plasma volume that occurs in the first days of exposure to altitude.
The combination is demanding: the body needs more water to compensate for what it loses breathing in a dry environment, just when the heart is already working harder than normal to compensate for the lack of oxygen. A player who arrives in Mexico City without adjusting their fluid intake is facing two physiological disadvantages at once, not one. We explain what signs indicate that the body is no longer compensating well for that loss in signs that you are not drinking enough water.
When FIFA banned playing at altitude (and why it reversed course)
In May 2007, FIFA banned international matches above 2,500 meters, citing player health and competitive fairness concerns. The measure directly impacted Bolivia, Ecuador, and Colombia, who saw their ability to host qualifying matches in cities like La Paz, at 3,582 meters, restricted. Then-Bolivian president Evo Morales called the ban "football apartheid." FIFA extended the limit to 3,000 meters a month later, and finally suspended the ban altogether in May 2008, after a formal protest from the South American Football Confederation.
The episode leaves an uncomfortable but useful lesson: altitude is a real and measurable factor on performance, serious enough that FIFA tried to ban it, but also manageable enough that FIFA itself decided that the solution was not to ban, but for each team to prepare better. Acclimatization, arrival planning, and a hydration strategy different from that of a sea-level match are part of that preparation.
What changes for a well-prepared team
The medical teams of the national teams playing in Mexican World Cup 2026 venues adjust specific protocols: arriving more days in advance when the calendar allows, monitoring urine to verify hydration status before training, and scheduled fluid intake throughout the day, not just during the match. The goal is not to drink more just because, but to anticipate a water loss that at altitude begins earlier and from a source that does not exist at sea level: breathing.
This applies not only to World Cup professionals. Anyone traveling to a high-altitude city, whether for sports or simply to explore it, faces the same math: more thirst than you feel, more water than you think you need. If you want to understand how much your body needs under normal conditions, before adding the altitude variable, we have the complete guide in how much water you should drink per day.
An opponent that doesn't appear on the match sheet
No 2026 World Cup scoreboard will say "Mexico 1 - Altitude 1." But any coaching staff that has played in Mexico City knows that this invisible opponent was on the field the entire match. It is fought with planning, with acclimatization, and, in the part that each person can control without needing the medical team of a national team, with constant hydration before thirst appears. For more context on how FIFA manages the other major environmental factor of the tournament, heat, see why FIFA stops games to hydrate players.
If this World Cup has you watching matches at odd hours or simply reminded you how little you think about drinking water until it's too late, here's the Fluye collection. It doesn't change the altitude of anything, but it helps with the part that does depend on you.
Written by the Fluye Bottle team