Sun Simiao, a medical scientist in the Tang Dynasty, said: "It is inappropriate to go out early in the morning and come back late at night in winter, which offended Han Wei." Go to bed early to nourish yang, and get up late to solidify yin essence. There is a saying: spring sleepy autumn sleepy, summer sleepy winter three months can not sleep. Chinese medicine pays attention to spring hair, summer harvest and winter storage, and winter is the season to recharge your batteries.

Methods: Adequate sleep should be ensured in winter health preservation, which is beneficial to the accumulation of latent yang and yin and body fluid. Remember to "raise Tibet" in beginning of winter's aftercare. Therefore, it is necessary to go to bed early and get up late, and do it at sunrise to ensure adequate sleep time, which is conducive to the accumulation of hidden yang and yin essence.