Every time you move large muscle groups at high intensity you incur quite a high oxygen debt that needs to be repaid. That repayment comes with a higher energy burn and an overall increased energy burn. Yes you will sweat and yes again, you will gasp for breath but you will also get to extend your endurance, test your VO2 Max and will get to work pretty hard. Make the transition from one exercise to the next as fast a possible and add EC and this workout becomes pretty hard indeed. Raise your knees to waist height during High Knees and your lungs will scream a little. It's still however a Level II workout which means you can adjust it to your capabilities as you go along.
Extra Credit: 1 minute rest between sets.
