I’m not sure if you were asking a question or if you’re trying to lead the discussion in a particular direction. Cardio doesn’t solely use cardio muscle, true,

I’m not sure if you were asking a question or if you’re trying to lead the discussion in a particular direction. Cardio doesn’t solely use cardio muscle, true, but your cardiovascular system is what you are targeting with the exercise and it does not need a recovery period, unlike other parts of your body you would exercise. You can do intense cardio every single day, or at least nearly every day, because the cardiovascular system works differently from your skeletal muscles. You should not do an intense deadlift session every day, because your skeletal muscles need time to heal. So I would in general not try to draw many comparisons between cardiovascular exercise and other types of exercise.