Someone who is considered 'advanced' is probably stronger and has more endurance than someone who is considered 'intermediate'. They should be conditioned to go longer and harder, and like the intermediate person, they continue to get stronger. If you are not getting stronger, then you are not progressing, and PROGRESSING is the key to being fit, NOT overall calorie burn. Burning lots of calories is rewarding, but it is only a small part of being fit and reaping the benefits of being healthy. Also, the number of calories burned varies from person to person and day to day, workout to workout, etc, etc.
For example, imagine an overweight, itermediate exerciser who burns 600 calories in an intense hour workout. Now imagine a very fit and petite (not all fit people are petite, and not all intermediate people are overweight but for the sake of the arguement...) exerciser who burns 250 calories but exercises for 80 minutes. We know that the more you weigh, the more calories you burn in a given workout. A person will also burn more calories if they are not as conditioned cardiovascularly(sp?)speaking, and so their heart must work harder to do the work. That will probably register as more calories burned. But actual calories burned does not mean you are getting a 'better' workout than someone who weighs less or is more conditioned, and it certainly does not mean that you are more fit. So, it is possible for the advanced person to get more fitness gains from a workout and burn less calories than the intermediate person who burns more calories.
I guess what I'm trying to say is, try not to get too focused on the calorie expenditure of working out. Yes, it is a nice number and can provide a basis of comparison. But it does not take into account how fit you are and the goal of working out should be to be fit (body and mind), and not burning tons of calories. If you forget about the importance of progressing, then you will eventually lose some fitness gains and possibly start regressing.
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