Anabolic Aerobics Part I

Well there's one more thing that should go. And that's the law that says cardio will kill your gains in muscle. Cardio should be apart of every program whether your goal is maximum muscle or serious fat loss. In fact cardio, if implemented intelligently, can even augment your effort in the weight room! That's right, you don't need to be come a slob to put on muscle. You can stay lean and even lose that spare tire in the process. Is it really possible to build muscle with out 6,000 calories a day?? You bet your sweet ass it is!7,14,17,18,20,26 And even more interesting, it happens in young, healthy people who have been training for years15,26,27. Its really a matter of how you go about it and how you manipulate your diet to maximize you bodies internal workings. This first article is going to focus on just how  cardio can help grow muscle.

First we need to realize that simply increasing caloric intake does not lead to muscle mass26,33. We can all agree that the types of calories (ie. Protein, carbs, fat) play a much bigger roll. Its also been widely accepted that keeping glycogen stores high is a determining factor in the rate of growth. This is why many bodybuilders find it necessary to consumer more carbohydrates than some endurance athletes. This is where cardio, and more specifically intense cardio comes into play. Glucose is transported by a protein molecule called, GLUT4, that basically sits on the surface of cells.

The more you have the more glucose can be carried into muscle cells. High intensity aerobic work greatly increases the amount of the transporters21. Intense aerobics also creates the same catabolic state and 3 hour nutritional window of opportunity as does weight training13,25. This is the first down fall of many bodybuilders. How many of you out there actually supplement a cardio session exactly the same as weight training?? That's what I thought. And this response stays elevated above normal resting conditions for literally days21,22

The Role Of Insulin

    However, you can't get any glucose into a muscle cell with out the presence of insulin, the king of anabolic hormones. If you don't control your insulin all day, every day, you are basically shooting a hole in the boat you're sitting in21 Both aerobic and heavy weight training increase insulin sensetivity11 so in the long run, less carbs are needed to reach optimal levels of  glycogen stores. There is also a strong correlation between the amount of insulin secreted and the rate of protein synthesis28,29. And, surprise, surprise, insulin responses are much higher to the initial dose of carbs after intense exercise.15 However, the long you are inactive, those high rates of synthesis drop off quickly with ever hour that passes30.

So for those of you who lift on a 3 day split, you may be wise to slip a short intense cardio session on those off days. And if you are someone who goes to lift twice a day, it would also be wise to make one of those times a cardio session instead of more weights. By lifting two times a day, you are setting yourself up for disaster. It seems that with every weight training session on a given day, the catabolic hormone response is amplified!25. But overall cortisol (the catabolic hormone) levels stay very low in people who go once a day, every day15 In fact, its been shown that people who incorporate 3 days of weight and 3 days of cardio gain more lean mass, and even with a negative nitrogen balance26. as much as a 4% increase in dry muscle. Not, fat free mass, not weight, not lean mass, pure stinking muscle. And a loss of 5% body fat ta-boot27

GH & IGF-I

    The most promising aspect of cardio work is its effect on the two remaining hormones that are paramount in muscle growth, growth hormone and insulin-like growth factor-I. Now, there has been some debate as to whether or not GH is really anabolic and increases muscle mass. Well lets say for argument's sake that it isn't. But one thing is for sure, its metabolic offspring, IGF-I sure as hell is!2,3,8,9. We all know that stacking on the heavy weights increases these two hormones rather effectively 1, but not many think of cardio doing that as well. in fact, cardio is just as effective as the heavy weights19,15,31. GH whether or not it is actually active in muscle growth is irrelevant when you know that it is the hormone that stimulates the release of IGF-I32. And it appears that as the intensity of the cardio increases, so does the amount of GH31.

And to top it all off, if for some unknown reason you decide to do more than one cardio session a day, the release of GH is magnified with every time19. What exactly is "intense" cardio. Well roughly 85-90% or your VO2 max, or heart rate26. If you can go for more than 20 continuous minutes, it simply isn't hard enough. The goal of intense cardio is to not so much burn off the 400 calories in the session, but to let your body do that as it tries to "fix" it self after the ass whipping you just dished out. the shorter your sessions, the less chance you run of hitting the catabolic wall25. However, the effects of IGF-I on muscle seem to be "local", meaning it has to be produced by, or introduced into the muscle4. And because contracting muscle has an insulin-like action (you probably call it the "pump"), all the extra movement from the cardio will be drawing more IGF-I in to cells. So it would be wise to find some type of cardio that uses a lot of different muscle groups.

So to bring this to a close, doing cardio during a "bulking" phase to stay lean or lose some extra fat will only magnify your efforts in the gym. Cardio increases your ability to store glycogen with less carbs and calories, it conditions our body to supress catabolic hormones for longer periods of time and it not only sets the muscle building stage buy producing an abundance of  anabolic hormone, but it keeps the process going at a high rate 24/7.

However, all of this means squat, unless you play your "nutritional timing" cards right. And in the next article, I'll explain how to stack the deck in your favor.