In industrialized societies most professional-level people do not do physical work for a living. Thus, we spend our days at desks, in cars or behind counters and remain seated on standing. So our muscles and bones get little to no exercise.

A sedentary lifestyle encourages the emergence of diseases and ailments.
This is the case of problems related directly or indirectly to the heart, weight, the motor apparatus and emotional balance. It has been shown that all these improve considerably when we get exercise.

Diseases that are alleviated
- Hypertension: The benefits of exercise are unquestioned: some studies report of 10 to 20 mmHg in the hours right after a bout of moderate physical exercise such as a walking briskly, riding a bike or swimming for half an hour. Oddly, research shows that the benefits of exercise are greater when the hypertension is more severe. This is because the heart is strengthened and oxygenates itself better, and this leads to a reduction of blood pressure. Exercise eases hypertension, lowers cholesterol and improves the heart. Even in the case of cardiac deficiencies, in which rest was recommended, now a program of moderate exercise is recommended.
- Type II Diabetes: this diseases raises significantly the risk of suffering a heart attack. Exercise helps lower the level of glucose in the blood because insulin is received better.
- Obesity: Exercise burns up calories and it is harder for reserves that cause weight
gain to accumulate.
- Osteoporosis: This is a kind of bone fragility common in women after menopause.
The disease evolves more slowly if women do exercise with weights. Also, women who have done exercise throughout their lives have a more developed bone mass than those who have not. 
- Immune system: A few laps in the swimming pool or kilometers on a bike boost the immune system. The body's defenses are stimulated and strengthened, toxins are eliminated better, production of endorphins is increased and that of catecholamines and corticosteroids goes down, raising the number of lymphocites.
- Mental health: Exercise lowers tension and helps us disconnect from problems that cause stress and anxiety. Exercise causes that pleasant sensation of physical fatigues that allows us to relax and is so different from mental exhaustion. Don't forget that endorphins make you feel good, and exercise makes your body secrete more of them. 

Exercise moderately
For all the advantages that come with exercise, it is careless to start running, swimming or climbing mountains without first seeing a doctor, getting a check-up and determining what kind of exercise is best for you, considering your age and physical condition. 

For sports to be efficient and healthy, they must be of average intensity and kept up over time. Five minutes a day will not do it. Nor will three hours every two weeks. You have to exercise three to five days a week for at least 30 minutes.