I would just like to add that morning shaves have been my SOP for most of the 30+ years that I've been shaving. There has never been any difficulty in waking myself up - I slap on some cold water. Your skin is a bit puffy in the am, anyway. (I'm sure the polar bears will attest to the bracing effects of the cold splash.)
I don't shave cold, but I'm much more alert after that initial shock to the system.
Cheers,
Ian