which is which?

Today I was struck down by a nap.  I mean it too.  One minute I was perfectly fine, and the next minute I was crawling to bed for a 20 minute nap with my favorite dog.  For informational purposes - my favorite dog is the one who doesn't pee on my pillow when she's po'd at me.

And twenty minutes later I was "fine".  Yes, I could have slept longer, but homework and housework are calling, and I know if I get too deep into sleep I could have a hard time waking up later.  But here's what I'm trying to figure out.  

Was today's nap the product of MommyHood (aka chronic sleep deprivation) or Marathon training?

I probably will never know, but I'm sure the 5am wakeup call (B) today had nothing to do with it.