For example,
heart attack is very chronic disease and it happens in early years if people not healthy, especially very
obese men can be heart attack. To be fit, people must do many exercises. For instance, according to
the results of a recent survey conducted by scientists, a large majority of people spend three hours in
a day for sports. Also, physical fitness can develop protection from chronic diseases. Everyone knows
old person who is grandfather or grandmother but he runs or goes to sports salon and he is never ill
even he is 80 years old.