Hamilton drops drinks bottle to save weight

Mercedes has been working hard to bring down the weight of its W08 design, after starting the season struggling to get near the 728kg weight limit for car and driver.

Although improvements have been made over the course of the first five grands prix, the team still needs to find further savings so it can start using ballast to help better balance the car.

So on the edge is Mercedes, and so close is the fight with Ferrari, that Hamilton has elected to sacrifice having drinks during the race to help save a bit more weight.

The lack of liquid will help shave off a vital kilogramme or two at the start of the race.

Hamilton's out-of-breath radio communication during his Spanish GP battle with Sebastian Vettel prompted questions about how physically demanding he had found the race, to which Hamilton revealed his deliberate lack of a drinks bottle.

"From Turn 1 to the end it was flat chat," said Hamilton.

"You're just using everything you've got.

"In that first stint, for instance, to stay on Sebastian was a killer.

"Also I don't carry drinks in my car either to save weight, so I'm not having a drink through the race.

"And then at the end, I used everything I had left when I jumped into my team and my heart rate hit the ceiling."

Mercedes motorsport boss Toto Wolff said he was not concerned about Hamilton sounding so exhausted on the radio.

"I think it was just an expression of how hard he was pushing," Wolff said.

"When you need to follow a car that close behind, you obviously haven't got the aerodynamic benefit of the guy in front. That is difficult.

"He gave it all and you could hear it on the radio."