3 schools of thought on cardio: 1. Dont do any because its catabolic, 2. Do low intensity, long duration (ie. 30-50 minutes) because it burns fat while youre doing it, and 3. Do intervals because it burns more calories after youre done.
Is cardio catabolic? It breaks down muscle protein. So, yes. I guess weight lifting is too, then. However, as long as its not excessive you can recover just fine. Eat protein. The theory here is to let diet do all the work. However, research consistently shows that adding cardio to a diet results in much more fat loss and less muscle loss. The problem with cutting calories is that there is no guarantee about what your body will burn. It will likely burn fat and muscle in a 1:1 ratio.
Lets take intervals next. Yes, more calories burned from this after done. But, again, no guarantee where calories will come frommuscle, fat, glycogen? Appetite will usually compensate for this work and make you eat or make you miserable if you dont eat. Also, weight lifting is interval training if you think about it. However, there is nothing better for getting your cardiovascular system in shape. I do this twice a week for that reason alone.
Low intensity cardio is one of the only known activities that will burn fat while youre doing it. This is as close to a guarantee that youre burning fat as youll get. IMO, this cardio is the BEST for fat loss. I recommend that you find your base level caloric expenditure without this cardio. What do you burn from your normal routine without this cardio. Multiply your weight by 14 if youre not over 12% bodyfat to get a good idea. If youre under 10% body fat multiply your weight by 15. My recommendation is to eat that amount and let this type of cardio do the fat burning. Dont cut calories unless youre trying to get paper thin cut. Whats great about this cardio is that its so easy on the body you can do it all the time. Try low impact stuff like walking or stationary bike riding or gliders etc... Try 6-7 days a week for 30-50 minutes first thing in the morning on an empty stomach. Thats the key to ensure max. fat burn. You must have an empty stomach. Secondly, Id do it after weight lifting. Thats not as good because youre muscles need to start repairing with a protein shake. Thirdly, Id do it before you eat a meal when youre hungry. Lastly, Id do it when youre digesting.
