Is a 10+ hour workout excessive?

I'm not a doctor or anything like that, but I know different people have different needs.  My husband can hike all day long and never realize it's been 8-10 hours.  I, on the other hand, notice if I walk up the stairs.  I'd think, though, that what you're describing might be excessive.  While I'd welcome the energy to do what you do, I'd worry.  If it was one of my children, I'd have them at the dr in a moment flat.  But if you've been doing this for a long period of time and feel good and healthy and have no side effects, then I don't see what harm there is.  If it's something new, though, or if you really feel poorly afterward, then I'd see someone.  No matter what, be sure to drink excessive amounts of water!