Cardio is one of the least glamorous and appealing aspects of exercise and physical fitness. Why? Because it’s boring.
Being confined to a treadmill for an entire hour five times a week does help you lose weight, but it’s dreadfully uninteresting. Maybe watching TV helps (which most gyms will allow you to do now while in the cardio area), but doesn’t that sort of defeat the purpose of exercising?
Besides, when you’re running hard and keeping your heart rate up, it’s hard to focus on anything else, much less a TV show that reminds you of fond memories at home on the couch.