A body is not considered strong how to live to 80 years old?

A person whose body is not considered strong, want to live to 80 years old, then we must work hard to make their bodies become strong, in the evening after dinner every day must go downstairs to walk, square dancing or do Tai Chi, so that they are physically strong at the same time always maintain a pleasant mood, then it must be able to live to 80 years old.