Depends on weather, since its winter in Canada for about 6 months out of the year we hibernate for the most part because its cold and dark so we only go for walks in the evenings/weekends when its mild temps, or on weekends we go to dog parks. Niether of my dogs have or develop any kind of annoying behavoiral issues when they're not exercised enough. My young Kelpie mix just brings toys or balls for us to throw around the house for him, or we play some tug, or some quick, fast and fun training sessions. Hide-and-go-seek back and forth recall game is a good way to tire him out in our house - especially with my boyfriend in the top story of the house and me in the basement - Thumper has to run up and down 4 short flights of stairs.
I did purchase Thumper a treadmill, I have a gym in my basement and I do exercise regularily because of the cold weather inside, so I have a couple of my own machines that I use, and while i'm working out for 30 mins to an hour I put him on the treadmill.. he LOVES it. I don't even have to ask him to go on the treadmill, as soon as he sees me put my work out clothes on, he bolts for the basement and sits and waits patiently on his treadmill for me to turn it on.
In the summer when we come out of hibernation, we will be out doors quite a bit on a regular basis so they will get tons of exercise. Thumper will get harnessed up and pull us on rollerblades, or we will go jogging (tons of nice paved trails around my house), and since we will have daylight until 9 pm we will go to dog parks in the evenings, hiking on the weekends, and we do lots of camping so in general they will be fairly stimulated but i'm sure they will be no better or worse behavoir wise then they are locked up in the house most of the time now during the winter.