I very much like this article from Fast Company magazine. It suggests new forms of personal risk management. Most of those interviewed try to leave their email alone, and either work on a combination of physical and motivational exercise, or on a large project that requires heavy lifting.
There's nothing lost by giving this approach a try. As one of the interviewees points out, if there is something urgent in email that first hour or so, you will undoubtedly get a text or phone call.
It's certainly difficult not to want to clean that mailbox down first thing. But I'm going to see what I can do to shift more completely to this model. Not turning on my computer or looking at email on my iPhone before I start to exercise might be harder than I think, but I'll give it a shot.