Haas' Romain Grosjean has warned that the heat and high humidity levels in Singapore could take their toll on drivers in Sunday's 61-lap race.
F1 drivers are obviously very fit athletes, and preparation for the Marina Bay event has been specific for many.
Toro Rosso's Carlos revealed that he trained in a sauna heated at 50-degrees to replicate the conditions which drivers will likely face in Singapore.
"This weekend is going to be particularly tough, especially this year with the new cars," said the Spaniard.
"I expect a tough weekend from the physical side, also from the mental side."
But the race's unique challenges, embodied by the physical demands linked to the twisty circuit and the sweltering environment, still put the drivers at risk of enduring a 'heat shock' contends Grosjean.
"Fitness has evolved but there is a high probability that we could get a heat shock and be in a pretty bad situation," the Haas river told Autosport.
"Normally your body manages to keep going through the race but when you get the chequered flag, everything switches off.
"The key is to drink throughout the race, even though it isn’t easy.
"Already on the grid, when you jump in the cockpit, you’re already sweating and you’re thinking, ‘I’ve got to go in there for two hours and it’s going to get warmer’.
"We know it’s one of the challenges of the year."
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