First of all, at a cardiovascular and pulmonary level. This type of  
 exercises are the most effective in burning calories and this is why  
 they can easily burn fat tissue, as long as they last more than 40-45  
 minutes without stopping. The energetic support of these efforts  
 Comes from the fat acids which are mobilized from the adipose tissue.

 The efforts of anaerobic type are responsible for increasing force and  
 muscular mass and for bone resistance. During this type of short and
 intensive effort the body cannot satisfy the need of oxygen. What
 happens is the so-called ' oxygen duty', recovered in the breaks  
 between the efforts. The most typical example is the break between  
 two series of exercises meant to work the same muscle.

 The effectiveness of fitness training is closely related to their weekly  
 practice. There are a minimum number of training’s necessary for
visible effects.

For the programs of anaerobic type (force) the experts say that two  
 training’s a week are necessary, each of 30-45 minutes. During these
 sessions, the whole body is trained every time.

In the case of aerobic training (resistance), their weekly frequency
 must be increased to three, each between 20 and 60 minutes.