One indisputable fact is that the average life span of humans has continued to lengthen throught modern history. In my country, the average life span of people are 75 years.The reason is that the lifestyle of people are better and better. In my point of view, there are three conspucious resons for this phenomenon: nutrition, exercises, and rest. First, to keep health we should try to refrain from consuming anything that includes sugar, fat or cholesrerol. Because these food can cause hypertension, we should eat more vegetables to keep balance of nutrition. The second element is exercise. Someone said “ if you do not  use it you lose it." Do exercise can make our stronger and more health. “We know reaction time gets slower when we become older and older, but activity is a big modifier” someone said. So doing exercises can make our more health. Finally, reast is another very significant reason for keeping health. According to the survy “Liver 10-2 point in the evening will step up their efforts, the blood will increase substantially by the liver. This is the body the liver filters the blood, self-recovery and the best time to blood. If you do not sleep, the brain, the body will rob the liver with the blood rush nutritionthat is bad for health. From this we can see the importance of rest. In short, making the time to stay healthy and you will not regret it.