I'd say it's incredibly common for a modern office worker to be engaged in email, meetings and chat for some 4-6 hours per day.

Not only does this leave little time to do actual tasks, that little time is also highly fragmented across the day.

It's a point I've made repeatedly on similar threads: the problem with modern office work is too much collaboration. Pretty much we spent the vast majority of the day figuring out what to do when, instead of actually doing it.