Data released by the Chinese Sleep Research Society show that 24.6% of people have inadequate sleep, and over 90% fail to achieve a good level of sleep.

　　01 Sleep Duration

　　Sleep duration is one of the common factors that influence sleep quality. The healthiest way to sleep is to take a “zi-wu nap.” “Zi” refers to the period from 11 p.m. to 1 a.m., while “wu” refers to the period from 11 a.m. to 1 p.m. Sleeping during the “zi hour” helps replenish vital energy and restore strength, whereas sleeping during the “wu hour” aligns with the body’s natural yang energy development. The ideal sleep duration is between 8 and 10 hours. For women, the optimal time for a “beauty sleep” is from 10 p.m. to 2 a.m.

　　02 Sleep Environment

　　The sleep environment is also a factor that affects sleep quality.

　　Generally speaking, the optimal microenvironment for sleep features a local body temperature of 32°C, a relative humidity of 50%, and an air flow velocity of 25 cm/s. In such a microenvironment, the human body feels extremely comfortable, which in turn effectively prolongs the duration of deep sleep. The softness and comfort of bedding are also crucial. The mattress should have just the right level of firmness and elasticity—neither too soft nor too hard—so as to help maintain the body’s natural S-shaped curvature of the spine and relieve muscle fatigue.