To improve, therefore, should “force” that is to say, he must submit to physiological stress rather high. Enough in any case:

• Cause a physiological imbalance.
• Set in motion processes to ensure homeostasis.
• Stimulate the improvement of these processes.

The problem is we can not long maintain a high intensity. That is why the intermittent drive is so popular among elite athletes: it can perform more labor intensive than the continuous type of training, without causing too much fatigue. The other problem is that “forcing” too much and too often, we may suffer from over training syndrome. There are no recipes: we must learn to tit rate the effort and know when to spare before it’s too late.

Curiously, some physiological processes do not improve even if they are put to the test regularly. For example, the ability to pass the digestive system to the circulation water you drink during exercise does not seem to improve, what we do in training. It is therefore necessary to “force” the drive to improve fitness and performance. It seems however that we can prevent many serious diseases that afflict much of the population physically active for mild or medium, provided this is done regularly. One thinks, for example cardiovascular disease, including hypertension, dyslipidemia (too many “bad” cholesterol carriers, not enough “good”), in type 2 diabetes, osteoporosis, to overweight.
“Volume” of activity and health benefits

The more a person is active, the more it withdraws to its health benefits. That’s clear. However, the beneficial effect of physical activity for health gradually tends to peak when the “volume” of activity increases. Thus, the sedentary person who increased physical activity and increases its expenditure and energy, for example, 1 000 kcal per week reduce their risk of many may be suffering from certain diseases. However, in a person already physically active, therefore healthier, an identical increase physical activity will not reduce as much risk of disease, since this risk is already low.