Thomas Tuchel has conceded that his England squad are not used to playing in the kind of temperatures expected at this summer's World Cup in the United States, Mexico and Canada.
The 26-man squad are due to fly to Miami on Monday to begin their preparation camp ahead of their opening match against Croatia on June 17.
"The conditions are not our biggest enemy but it is not to our advantage after a long and very demanding season for our players," Tuchel told Sky Sports News.
"We are not used to being in this kind of heat and humidity, and even altitude if we play in Mexico.
"There will be a lot of challenges in this World Cup. The heat is one of them but we are prepared already."
Tuchel and the Football Association began making preparations for the conditions at least one year ago.
Last June, during a warm-weather training camp, Tuchel had his squad take specially-devised digital capsules which measured the internal temperature of a player's body and how quickly they were able to cool down.
Players also trained in specially-heated tents to mimic the conditions at this summer's tournament.
"We know the individual reaction of the players to the heat and we have cooling strategies in place," Tuchel continued.
"We've had help from Team GB and specialists all over the world to come up with solutions that help the players to adapt.
"We know exactly the amount of time we want to expose them in pre-camp, the ideal amount of time that you should train in the sun and that we also don't do too much."
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Following their opening game against Croatia in Arlington, Texas, England will face Ghana and Panama, two teams who will likely be more naturally acclimatized to the conditions.
"Then the reality is that the first game [against Croatia] is indoors and the air conditioning is on, so it should not be a problem. From there, we have to adapt," Tuchel added.
"It is a factor but it should not come across that we are already making excuses. It's just not in our favour and it is an obstacle to overcome."