Well, I think a dog will adapt, if you leave him alone for several hours, he will suffer. But most likely not complain.
Best case only his energy levels will be low and his physical activity will be below a healthy level. Dogs that sleep all the time do so because there's nothing better for them to do.
If you work and noone can take care of the dog, you shouldn't get one, it would be very selfish.
Ideally you have kids and can share the responsibilities with them. Dogs are great, but you don't wanna live with the guilt of having an animal that you can't give a good life.
