Most people know that exercise is an important part of any weight loss program, but there is considerable confusion over what type of exercise and how much is needed to produce maximum results. Even experts cannot agree as to what the "right" exercise is to produce weight loss, and in part this confusion lies in the fact that many experts rely on only a partial analysis of the available research on exercise physiology, and there is often a tendency to make "one-size-fits-all" recommendations, when the reality is that different people will actually get different results from different approaches.

Let's begin with what the current research on exercise physiology tells us. It is well-established that it takes approximately 30 minutes of any kind of exercise for the body to burn off its glycogen (stored sugar) reserves and begin burning fat. So, most experts recommend at least 30 minutes of exercise, and generally 60 minutes or more may be recommended to get a good amount of fat burning. Now, if you are going to be exercising for 30 to 60 minutes, or maybe more, what type of exercise would you be able to do for that length of time? It probably would have to be low to medium intensity. In other words, you're probably not going to be able to run full speed or do any other type of high-intensity exercise for 30 to 60 minutes without a rest, unless you happen to be an elite athlete, and even then you'd be struggling. So, by default, the common recommendation for exercise to lose weight has been 30 to 60 minutes of low to medium intensity aerobic exercise. Aerobic translates to "in the presence of oxygen", which in common language means that aerobic exercise is any type of activity that you can do without gasping for breath.

In recent years, some experts have changed their recommendations to using a more intense anaerobic ("without oxygen") exercise program for weight loss. This would include things like intense weight lifting, and something called "interval training". Interval training involves brief bursts of high intensity activity with periods of rest or low intensity activity in between. For example, you might run full out for 30 seconds or a minute and then walk for a minute or two until you catch your breath and then run again full out for 30 seconds to a minute, walk again, etc.. Since this type of exercise is much more physically demanding, it is done over a much shorter overall workout period - perhaps 20 to 40 minutes (with half or more of that time being rest or low intensity activity), as compared to the 30 to 60 minutes of continuous activity as recommended for aerobic exercise. The question is, how do the two types of exercise compare in terms of their ability to promote fat burning?

The aerobic exercise promoters point to the research that was mentioned earlier that has shown that any exercise, no matter how intense requires at least 30 minutes to use up the body's stored glycogen (the body will normally burn glycogen before it will burn fat) before fat burning can begin. So, they say, short periods of even highly intense exercise won't burn much fat and is therefore not a good choice for promoting weight loss. But they are only seeing part of the story.

It is true that you must exercise for at least 30 minutes to begin to achieve fat burning - but that's at the time you are exercising. Brief bursts of intense anaerobic exercise does something that even quite a lot of low to medium intensity aerobic exercise does not. Intense anaerobic exercise stimulates the production of growth hormone, which is a strong stimulator of fat burning. The thing is, the release of growth hormone triggered by intense anaerobic exercise comes 24 to 48 hours AFTER the exercise, and then it produces considerably more fat burning than is possible with all but extremely long periods of low to medium intensity aerobic exercise.

Because of this effect, most people will lose weight much more easily by doing shorter periods of more intense exercise. 20 to 40 minutes of heavy weightlifting, interval training (which could be done on foot, on a bicycle, swimming, kickboxing, etc.Any kind of activity in which there are periodic bursts of intense exertion interspersed with rest periods, or periods of low intensity activity is typically preferable in the long run for weight control than even long hours of lower intensity aerobic exercise.

Now, you'll notice that I said "most people". There is an exception to the rule. Anyone who is seriously emotionally or physically stressed in his or her daily life is prone to overstimulated adrenal glands. The adrenal glands do a lot of things in the body, but with regards to weight loss, they produce two hormones. One hormone is cortisol, which promotes fat deposition in the lower abdomen. This is typically a saggy, pendulous fat held below the waistline. The other hormone the adrenals produce is adrenaline (also called epinephrine), which actually promotes fat burning. Since the adrenals produce cortisol which causes fat deposition and adrenaline which promotes fat burning, you might assume that these two hormones cancel each other out. Unfortunately, cortisol production can be carried out by a much longer time by the adrenal glands than can the production of adrenaline, so long-term, the effects of high cortisol production (deposition of fat in the lower belly), will overcome whatever fat burning might occur from the short-term adrenaline production.

The adrenals are influenced by physical stress as well as mental stress, so for someone who is under a lot of stress in general in his or her life, high-intensity exercise will only add to the total stress and will tend to make the adrenals produce a lot of cortisol, and therefore will tend to promote lower abdomen weight gain. That's right - the wrong kind of exercise in this situation can cause weight gain! This can be the source of considerable frustration when one is faced with the situation in which he or she is working out very hard to burn off that lower belly bulge, but never can seem to get rid of it. Due to the fact that the intense exercise is causing even more cortisol to be produced, their efforts are counterproductive. Because of this effect, it is recommended that people under a lot of stress and/or who have most of their weight held in the lower abdomen stick to relatively low intensity aerobic exercise. This type of exercise tends to help with stress control and lowers cortisol levels, allowing the lower belly fat to gradually be burned off.

I hope that this article has given you a better concept of how to maximize your exercise routine for the best possible weight loss results.