Yeah, you should really try to step it up a bit. They sound like big dogs who need a lot of exercise - if I were you, I'd aim for 1 hour of walking or at the very least 30 minutes of very brisk walking every day, then see if that helps. My dog is bred to be a lapdog and weighs all of 8 pounds at his fattest, but if I don't take him for a walk for 2 days, he's bouncing off the walls and whining at everything.
It can get frustrating, but then I think about it - if I were locked up in a house without the ability to use a computer, read a book, watch TV, or play with friends, I'd probably be pretty stir crazy too!
Edit: labs in particular are notorious for being really high energy and requiring a lot of exercise, particularly as puppies. Maybe some rousing games of fetch in the yard or something might help?