Blood vessels are the 'supply routes' that transport oxygen and nutrients to body tissues, including muscles, and carry waste products away for muscular growth, repair and recovery. So, according to Parillo, aerobics can actually enhance recovery from weight training and increase muscular growth by developing the circulatory pathways that provide nourishment to the muscles. Cardiovascular training is important for good health, for fat burning, and for muscle-building. Losing muscle has more to do with inadequate diet than with excessive aerobics. You are not eating enough protein.
Protein is the only nutrient that can be used to build muscle.
To stay on the anabolic side you must eat five to six protein containing meals every day. Each meal should be spaced out approximately three hours apart. Research has proven that if you are physically active, you need a minimum of .8 grams to 1 gram of protein per pound of body weight. Bodybuilders may need even more. Your carbohydrates are too low.