For warmth

the difference in your body temperature between climbing and then suddenly descending can feel *massive*.

It's usually pretty cold when you get to more than 2000m, even in July. But on the way up the mountain, you nonetheless get really hot - you're putting in loads of effort, *and* you're going pretty slowly, so there's not much air rushing by you cooling you.

So you're wearing very little, to avoid overheating - many of them will even have their jerseys unzipped, revealing their skinny torsos.

Suddenly you get to the top. You're soaked with sweat. Then you start descending - and suddenly you're going very fast through the cold air, which is rushing by you. And you're putting in very little effort, so not doing anything to keep yourself warm.

And the descent might be a long one, like today - 30km, so it'll take half an hour at least.

So half an hour of flying downhill through cold air. Your core - and your extremities, fingers and toes etc - can get very cold very quickly. The contrast can be a real shock.

Turns out that stuffing a newspaper down the front of your jersey can make a big difference. Fans at the top hand them out to riders, and have done for years.

Posted By: Tricky Hawes, Jul 19, 15:19:40