Well, the question is, what does it take to burn fat w/ out losing that precious muscle?
Personally with my body, jogging, usually a 12-15 min. mile pace for 40-50 minutes is where I feel like I am in the fat burning zone. I am not panting and it takes me about 20 minutes to feel the burn and begin sweating.
(I am also a very heavy sweater) "Exercising" whether it be jogging, walking, jumping rope, etc. at a constant pace for an extended period of time causes fat breakdown. In the article there are two graphs which clearly show that fat breakdown is higher after a period of fasting which is basically sleep. Fasted Cardio.
A few main points taken directly from the article that are relavent to this issue are:
Improved lipolysis (fat breakdown) and direct fat oxidation (fat burning).
A rate of fat loss that's satisfying to any intelligent and experienced person (about one-half to one pound per week)
Little, if any, interference with a person's usual bodybuilding program.
It's pretty simple. If you want to gain muscle mass and lose some of that flab then this is a scientifically proven option.
Here's a link to the "100 Workouts from Ripped City" article. http://www.T-Nation.com/readTopic.do?id=927737