Because milk is rich in calcium, middle-aged and elderly people can drink it before going to bed, which can make up for the low blood calcium at night and protect bones. At the same time, milk has hypnotic effect. The best time to eat fruit is before meals 1 hour. Because fruit belongs to raw food, eating cooked food after eating raw food will not increase the number of white blood cells in the body, which is conducive to protecting the human immune system. 8 am to 10, and 4 pm to 7 pm is the best time to bask in the sun. At this time, the sunlight is mainly the beneficial ultraviolet A beam, which can make the human body produce vitamin D, thus enhancing the anti-tuberculosis and osteoporosis prevention ability of the human immune system and reducing the incidence of arteriosclerosis. The skin's metabolism is most vigorous from 24: 00 to 6: 00 the next morning, so it is best to use beauty and skin care cosmetics before going to bed at night, which can promote metabolism and protect skin health.