This is a subject that many readers have asked me to expand on. Before I proceed any further, I should point out that this article is actually an excerpt from a much bigger and complete article on Aerobic exercise and FAT loss. If you are interested in purchasing the article, please email me directly. The original article aside from explaining the technical aspects of aerobic metabolism also contains an actual Aerobic Exercise program designed for the individual seeking primarily body fat reduction.

Lets start out by dispelling a common myth regarding fat loss. Many people foster the belief that specific "problem" areas of the body can become leaner by being trained with specific exercises. For example, many people believe that doing countless sit-ups or other abdominal exercises will eliminate body fat from the midsection and will tighten up the area. In a similar way many people believe that doing specific exercises which target the upper legs and buttocks will reduce fat in these areas and help them tighten up. Unfortunately this is nothing more than a common misconception as we will soon explain below. There is a basic principle of fat loss which states that: SPOT REDUCTION IS NOT POSSIBLE. What that means, is that it is not feasible to reduce fat accumulation in a specific area without affecting the whole body. I should actually put it in a more correct perspective by saying that it is not possible to spot reduce fat through exercise. The only way to reduce fat from a problematic area without affecting the rest of the body is through Liposuction. There are many risks associated with liposuction as well as a hefty financial penalty but they all fall outside the scope of this article and therefore I will not get into them. Suffice to say, that if you are concerned about reducing your fat percentage and at the same time improve your overall state of well being, lower your blood pressure, increase your longevity, lower your cholesterol, increase your self esteem and tone up your whole body, there is only one proven recipe: The combination of Aerobic exercise, Supportive nutrition and Resistance Training.

I have already touched upon the component of resistance training in my article "An introduction to muscle development" as well as the article "Designing a Fitness program for overall Body Conditioning and weight control" so here I am going so expand only on the aerobic exercise component.

I will start with a brief review of the fat burning process insofar as human metabolism is concerned as this will help clarify the specifics of the aerobic training discussed later on. If you have not already read my article "The Atkins Diet and other Low Carb based plans" I would urge you to do so since it will provide you with more information regarding the way our bodies "burn" body fat.

There are four sources of energy in our body: First, there is Creatine Phosphate which can very rapidly provide energy but unfortunately the amount stored in the muscles is so low, that it can only provide energy for no more than 15 seconds. Secondly, there is Glycogen which is primarily derived from the carbohydrates we consume through our nutrition. Foods that contain sugars (simple or complex) and starch are reduced to glucose during the digestive process and eventually enter the bloodstream where they are transported to muscle cells and stored as glycogen. Glycogen remains in the muscles until the body requires energy to complete a task such as an exercise workout. In this case, the glycogen storage is converted back to glucose and undergoes a process called glycolysis during which it produces ATP (Adenosine Triphosphate) the only source of energy that can be used for muscular contraction.

However, after a period of approximately 10 minutes in the workout, the glycogen starts becoming depleted and the body turns into alternative sources of energy in order to build ATP for muscle contraction. There are only two more available sources: Fats and Proteins.

When fats are consumed though the diet, they undergo a digestive process through which they are stored in the body as Triglycerides. When glucose becomes depleted and extra energy is required the Triglycerides are called upon to provide energy by entering a chemical process known as Krebs cycle during which they produce ATP. This process however is very slow. As a result, the body is not able to engage in a very intense workout while relying only on fat recycling for its energy. However, we should not forget that there is also protein, the last resource our body can use for energy production. Unlike fat, protein can actually be converted to glucose and eventually used as energy resource but the release of energy from protein is a also a very slow process. In addition, protein can not directly be converted into glucose. It has to be broken down to its primary building blocks the well known amino acids which in turn will be transported to the liver and converted to glucose.

The problem is that there are only two sources of amino acids. First, the amino acids already circulating in the blood as a result of our last protein meal and secondly the ones derived from the breakdown of our own muscle tissue. Please read this last sentence one more time because its importance is crucial. Our body will start breaking down our own muscle tissue in order to release amino acids which can be converted into glucose and used for energy production. Obviously we would want to completely avoid this situation. Muscle tissue is extremely valuable to be consumed for energy. Therefore, you need to make sure that your body does not enter the stage where it starts breaking down its own muscle for energy production, otherwise you would be working out to decrease your muscle.

There are three ways to avoid this situation:

• First, keep your aerobic exercise in moderation so that you stop just sort of the stage where the body starts digging into its own muscle for energy production. This point typically begins about 15 minutes into your aerobic workout. Put more simply, if you are looking to avoid muscle breakdown (and you should), it would be wise to keep your aerobic exercise limited to 15 minutes.
• A second way would be to make sure that the body has an abundant supply of amino acids already circulating within the blood so that it does not have to derive them by breaking down muscle. Many athletes achieve this by consuming a liquid amino acid supplement half hour before the workout preferably on an empty stomach (which means that they have not eaten for at least two hours before). There are some other risks involved in this technique and that is why it is used primarily by experienced athletes.
• A third way to counter the break down of muscle is to stimulate muscle development through another workout, therefore replenishing the muscle being consumed by new muscle being built through resistance exercise. This means that you will need to also incorporate in your exercise schedule a resistance training routine which will stimulate muscle growth and replenish the amount of muscle being consumed. If you are following this route make sure to do your resistance training not more than 2-3 times per week on alternating days. Your aerobic exercise should take place on the rest of the days with at least one day of the week, (two days for beginners), being devoted to complete rest. If you follow this route, your aerobic workouts could be up to 40 minutes long if they are in moderate to low intensity or up to 20 minutes long if they are of moderate to high intensity.

Lets expand a bit on the reasons we want to avoid breakdown of muscle tissue. Muscle cells contain rod-shaped bodies known as mitochondria which is the only place where aerobic metabolism and therefore fat "burning" can take place. Consequently it makes sense that the more muscle you have, the more mitochondria exist and the more fat you are capable of "burning". Breaking down your own muscle tissue would reduce the number of mitochondria and your ability to burn fat, a situation you definitely want to avoid.

As you can see, in order to optimize aerobic training for fat reduction, you need to take many factors into consideration, many of which are explained above. There are even more factors that should be considered such as the specific exercises used, the amount or reps and sets, the duration, frequency and type of activity to name just a few. That is why your best bet would be to consult a knowledgeable Personal Trainer who will be able to steer you towards the right path to fat loss. But for those of you who are going to proceed alone, a consideration of the above principles should help you make the right choices and decisions when designing an aerobic program targeting fat loss.

Best wishes for your success. As always, Train Smart, Train for Life!!