Lewis Hamilton conceded the summer heat was a factor for drivers after he claimed pole for Sunday's Spanish Grand Prix.
The reigning Formula One world champion joined team-mate Valtteri Bottas to complete a front-row lockout for Mercedes, with Hamilton needing a top-three finish in Barcelona to achieve a record 156th podium finish.
But the Briton revealed the sweltering conditions at the Circuit de Barcelona-Catalunya, which would in normal circumstances host the race much earlier in the year, had posed new challenges.
"It's the first time I've been here in Barcelona when it's been this hot," Hamilton, who has won in Spain in each of the past three years, told Sky Sports.
"The problems are all physical – it's just the amount you're able to brake now, the amount you're allowed to apply to the brake, is even heavier than before.
"There's a lot of stress through your core, you're flat out through turn nine, so a lot of stress on your neck, your whole body just wants to move to the side of the car and as it's so hot you have to be even more careful on throttle to not overheat the rear tyres.
"Physically it's tough, it's so fast round here, the forces to our body are pretty intense and the tyres are what we are really struggling with.
"You see drivers crawling around on the out lap just to keep the temperature out of the tyres – but even with those slow laps, the temperature is rising, that's what you're trying to manage on the lap.
"I couldn't go quicker on my second lap, which I thought I could but this wasn't a great lap, but the first one was decent, I guess, which did the job, thankfully."
Bottas was rather more downbeat after losing time to his team-mate over the last sector of the circuit, resulting in the Finn missing out on top spot by 0.059 seconds.
"All day today I've been struggling in sector three. Of course it is annoying but Lewis did a good job," Bottas said.
"I saw my long runs on Friday were competitive so I will have the pace but the start will be the best chance."
Red Bull's Max Verstappen took third and he felt that was the best he could hope for.
"It is the maximum we can do at the moment," he said. "All weekend we have been P3 so pretty happy with that.
"Yesterday the long runs were not too bad but it is a different day so we will see.
"I felt happy in the car, I hope I can apply a bit of pressure. It is very hard to overtake here but we will do everything we can to be close to them and make it difficult."