This is a really tough workout and definitely not designed for everybody or for different fitness levels. In fact, you must be in really good shape and good health to attend a class and do very well with high intensity interval training. Just because the workout doesn't seem all that long (forty five minutes on average), the fact is there is very little rest between actual intervals. The intervals last one minute take you from one station (and there were twelve!) to the next with a thirty second rest period which is very little. I thought I would enjoy it and I really didn't. No one from Fit36 called me as they said they would to follow up on my first session and this shows how little they really care.