2026 World Cup: England v Mexico – Five and a half hours left in chaos.

Dr Barney Wainwhite, a senior researcher at Leeds Beckett University, told BBC Sport earlier this week how altitude can affect athletes.

“Maximum aerobic capacity is reduced by about 10% at this type of altitude,” Wainwright said. “And that has a knock on performance.”

But does starting at 12:00 local time instead of 18:00 make a difference?

“If it’s hot, the heat can have a double effect with the altitude,” Wainwright explained.

“When there’s less oxygen in the air, it means less oxygen in the blood. This affects your ability to exercise and exercise.

“It also removes the mind. And the brain is important to us, because we need oxygen in the brain for decision-making, visual processing, things like that, which is important in football.”

Wainwright added that while the forecast was for 21C, fans and the temperature could add a few degrees on the pitch.

But this may not be enough to make any real difference to players.

“That makes it a little more difficult,” Wainwright said. “But overall, from a height perspective, it doesn’t make any real difference to them.”

Although the early game may affect the players’ rest.

Altitude can affect sleep patterns, and an early start would have had no chance.

However, Wainwright added, the chance of an evening of thunderstorms could be beneficial for England, giving them a chance to take a break from the effects of the high altitude.