I read an article while on the bike about cardio and the amount you should do for greatest effect. The article seemed to be well documented and based in scientific fact and quoted studies. The point I took from it was that you should do cardio, but no more than 40 minutes at a time to add muscle. Any more than this made you catabolise lean muscle. Something along the lines of you body has burned its glycogen stores and goes lookin for fuel. Your muscle being a great erady supply. Any of you pros agree or disagree with this? The mag was Muscle Media which is now out of business, but they seemed to make sense.