人的一生如从出生算起可分幼年、少年、青年、中年(壮年)、老年等五期。当然根据需要可更简化或更细分,如划分出围产期、超高龄期等。至于从生理学角度是否应从胚胎期算起倒是应该讨论的问题。老年期的开始目前多以60～65岁为界。无论在生理上或临床上老年与青壮年均有明显不同,所以恰如小儿科由内科独立一样,有的医院、医学院校已成立老年病科及老年 A person’s life can be divided into five periods, such as juvenile, juvenile, youth, middle-aged (strong), and old age. Of course, it can be more simplified or subdivided according to needs, such as dividing the perinatal period, super high age and so on. As for whether it should be considered from the physiological point of view, it should be discussed. The beginning of the old age is currently bounded by 60-65 years old. No matter whether it is physiological or clinically different from old age and young adults, it is just as if the pediatrics are independent of internal medicine. Some hospitals and medical schools have established geriatrics and elderly people.