sleepy doodle question

Good morning Angela, it is not uncommon for adult dogs to sleep a lot...and older puppies sometimes grow into that pattern too. I wouldn't be too concerned so long as he does show signs of energy and playfulness at times during every day.
I think that the heat can, indeed, make a difference in their energy level. Unless there are other things about his behavior that troubles you, I don't think that a vet visit is immediately necessary, but I would certainly discuss it with the vet if you get a chance. (I often call my vet's office with questions and the vet calls me back with answers.)

Just watch out for heat stoke and you would be able to tell the get real shaky and weak otherwise he probably is just worn out from the heat and playing, mine lay around quite a bit when it is very hot.

Dakota also slows down a lot in the heat. Last week we were in the mid 90s and he had no interest in being outside--just wanted to be inside lazing around! It's now in the mid 70s and he's making up for his laziness by being an all day wacky doodle! :wink:
Diane (and Dakota)