There's a smarter, simpler solution for working out that you'll see in just a minute that eliminates boredom and takes about 1/3 of the time of traditional cardio workouts. (metabolicmayhem.net)
Not only will you be killing the calories (in half the time of traditional cardio workouts), but you are building muscle at the same time. (fitbodyhq.com)
Cross-country skiing ranks up there with a more traditional cardio workout, Dr. Miller says. (health.com)