I would certainly have to disagree with my fellow reveiwer from Iceland. I am 30 and would certainly not consider myself "old" or out of shape. As someone who has been enjoying the benefits of exercise since the age of 16, I would have to say the the Five Day Fat Burner is a great workout for all ages and all levels of fitness. Granted, the workout can be made much easier if you break it down into its individual sections, this being ideal for those people who are new to exercise or those who have limited time. However, when all five sections are done as a whole, they provide a good aerobic workout and some solid body conditioning. I consider myself to be reasonably fit and this workout challenges me aerobically and also leaves me suitably sweaty and flushed! The good thing about this workout, as with all RC workouts, is that there is always a member of RC's team showing a different workout level, so you can keep the level low if you are new to exercise or want an easier day, or really take the level up by adding jumps and high impact moves if you are more advanced.