not only that, their neck muscles are probably so developed you could not hang them

imagine taking 4G turns and the acceleration/deceleration Gs in their cars for hours... that's not just for races but they do a lot of testing too..
i remember one year, about 3 fellas crashed their cars in the opening lap of the Monaco GP and it was at the other side of the lap.. they all promptly got out of their wrecked cars and ran back to the pits, jumped in their spare car and started the race!
they were in full leathers and did not take their helmets off!
their upper body strength is amazing too as they have to wrestle with the steering wheel of the car.. those hugeass wide tyres, gripping so well will imparts a lot of force on the steering.. and now they are all riding the kerbs, the vibrations must be amazingly hard..