Pirelli chief Paul Hembery admits he is shocked by the levels of G-forces on F1's wider 2017 cars, which he thinks would be impossible for "a normal human being" to drive.

Pirelli's chunkier tyres are a big part of the new regulations which have come into play this year, which were aimed at making Formula One cars more physically demanding for its drivers, with higher levels of downforce dramatically increasing cornering speeds. The Italian manufacturer promised a five-second drop in lap times compared to 2015 -- something Mercedes' Valtteri Bottas achieved on the third day of pre-season.

The early indications from pre-season are that corners such as Barcelona's 280 km/h Turn 3 can be taken flat out, something Hembery thinks highlights the huge demands of F1's new generation of car.

When asked about the increased loads on this year's cars, he said: "It is quite shocking. Even now, you are talking 5G corners ... a road car, top Ferrari, Lambo, [would be] 1.2 or 1.3G. These are getting to levels now that, I don't know....

"Maybe some clever doctors will tell us that we're getting close to blackout point, I don't know what it is. But certainly when I was looking at Turn 3 it was quite impressive. I'm sure a normal human being wouldn't be able to."

With Pirelli expecting one-stop races to be the norm in 2017, Hembery thinks drivers are going to encounter some intense races later in the year -- especially at circuits where heat is an issue.

"It's one of those fun fair rides isn't it, where you arrive at 5G, make you feel a bit queasy. It depends what circuit you are at. I would think a stint at Silverstone for 30, 40 laps is going to be pretty exhausting for a driver. Well very exhausting, I think even [here at Barcelona] when you add 20 degrees [Celsius] and they are actually going flat out in race trim.

"Physically I think it's going to be a huge challenge for the drivers. Of course they are all great athletes today, they do a lot of preparation. You think if we go three seconds quicker than what we've seen already, which is like three years' development normally, that's amazing performance."