Piano may no longer be the tradition it was in the Giro but today's stage covered 26 kilometers in the first hour, which is an indication that someone is trying to keep the tradition alive. During my 50 mile race this Sat, the only time we were riding this slow was during the roll out. And our race wasn't even particularly fast. For a group of professionals to ride this slow it's unlikely that anyone's heart rate has even reached zone one. It's barely recovery riding.
It won't last. I'm sure the sprint will be bedlam and, prior to it, I'm sure there will be some attacks. But most of the riders are probably pretty psyched to get some rest because tomorrow it all changes. The next week and a half are absolutely brutal as the race hits the mountains. If you haven't been paying attention, now's the time to start.
Here's some crazy mountain racing from the Tour a few year's back.