Mine don't get 4 hours, for us it varies through the winter months due to my increased work schedule. Some days they get 20 minutes of physical exercise, flirt pole, bicycle, or fetch, and others they may get closer to an hour divided up throughout the day. We go for walks 4-5 times a week, but they're not very long, maybe a mile or so, I hate neighborhood walks, too boring, so we mix in OB and we play tug along the way. Come spring will add in different length/difficulty hikes. We do take days off and all three dogs do fine with it.