It does! You’re doing three four-minute sets, so that’s 12 minutes of exertion. In the beginning it may take a little longer between sets because your heart and lungs need to learn how to do this. When you’re in your exertion zone, your heart is pumping good and strong – then you need to recover… let your heart rate return to normal. After you do this for awhile, the time between exertion and recovery will shorten… you’ll be doing your workout in minutes.