For the 2026 World Cupthe ranking will not only be based on the quality of the workforce or tactical plans, as Valérie Bougault, Lecturer, University of Côte d’Azur) points out in an article in The Conversation. Spread across 16 cities and 3 countries, this World Cup becomes a giant laboratory where extreme heatL’altitudethere pollution and the
time difference can weigh as much as a fit striker. An analysis published in the journal Sports Medicine already warns that certain stadiums will far exceed the risk thresholds for the health of players.
The researchers recall that 14 host cities showed average temperatures between 19.1°C and 32.7°C in June-July, with a wet bulb temperature WBGT (wet bulb temperature or WBGT temperature) above 28°C in the vast majority of cases. Added to this are nine matches at altitude in Guadalajara and Mexico, sometimes very polluted air in Western North America, and travel across several time zones. Victory could go to those with the best environmental plan, not just the best game plan.
Extreme heat: the number one opponent of the 2026 World Cup
The central indicator will be the WBGTwhich combines temperature, humidity, solar radiation and wind. According to the study published in Sports Medicine14 of the 16 cities exceed 28 °C of WBGT, and 6 can reach 30 to 35 °C. The American College of Sports Medicine already recommends limiting intense exercise in these areas, while FIFA mainly provides refreshment breaks of three minutes per half-time for all matches.
At the 2014 World Cup, WBGTs above 28°C caused the distance traveled at high intensity and the number of sprints to drop, with possession time increased by approximately 25%. The game slowed down, with less pressing and more short passes. To limit breakage in 2026, researchers recommend 10 to 15 days of heat acclimation, or at a minimum shorter protocols of five days, supplemented by sauna, hot immersion and hydration strategies enriched with carbohydrates and electrolytes.
Altitude of Mexico and Guadalajara: trap or hidden advantage?
Nine matches will be held in Guadalajara, at 1,566 meters, and Mexico City, at 2,240 meters. At these heights, oxygen partial pressure drops, reducing aerobic capacity and delaying recovery. Data from the 2010 World Cup in South Africa already shows a 3-9% decrease in total distance covered and up to 21% in high-speed runs above 1,200 meters, especially among midfielders.
Altitude training can turn this handicap into an advantage. “Live High–Train Low” type approaches over 10 to 14 days provide gains of 3 to 4% in hemoglobin mass, therefore better oxygen transport capacity. Microcycles in a hypoxic chamber or shorter “Live Low–Train High” strategies are considered more realistic for tight preparation, while strengthening the psychological resilience of players to demanding environments.
Pollution, allergies and jet lag: these details that break your legs
Host cities will also expose players to varying levels of ozone, fine PM2.5 particles and nitrogen dioxide, worsened by recent wildfires around Los Angeles, San Francisco, Seattle and Vancouver. The scientific journals cited by the article Sports Medicine link these pollutants to reduced lung function, slower sprints, reduced total distance traveled and less effective decisions, especially in players from less polluted regions.
Finally, the
time difference further complicates the situation: between Europe and North America, the difference reaches 6 to 9 hours, and certain selections will travel up to 16 to 19 time zones. Medical consensus recommends gradually adjusting sleep hours one to two weeks before departure, increasing hydration, carefully managing exposure to light and caffeine, then very quickly aligning training times with those of matches. For staff, integrating climate, altitude, air quality and biological clock is becoming a key skill in the same way as video analysis.