Not saying this is what you should do, and I can’t speak to how it would affect results of the challenge but I normally run 2 days a week approx 5 miles each time. I am continuing to do this, since I really enjoy it during the summer months. I am counting those as my 2 cardio sessions. Again, make your own choices but that is what I am choosing to do – feels so good to get outside in the mornings and enjoy a run. Summer is short here in Canada, gotta make the most of it!!