Go running! Run is one of the oldest forms of cardio. It's proven, tested, and effective. The fluidity of running allows the body to move in its natural pattern. It also allow one the opportunity of one to connect with mind and body.
One of the most asked questions I get from people who don't run is - What do you think about while you run? I don't listen to music. I don't listen to podcasts. I mostly run solo. After(Fitness Challenge Mens)
How Do You Compare to the Average Road Racer? Runner's World & Running Times actually surprised that I would be considered average in terms of my previous times. Still not happy with them but there's that.