Night sweats, a common perspiration disorder, occur during sleep and stop upon waking. Night sweats involve not simply sweating a lot at night, but literally drenching the bed. A healthy person produces between 500 and 1,000cc of sweat each day. A person with a perspiration disorder will produce much more. Although the causes of night sweats are many, generally they are symptomatic of underlying disease. According to Chinese medical theory, night sweats are associated with a yin essence (body essence). The diminished state is due to a depletion of body fluids and nutrients. Symptoms include flushed cheeks, warm palms and soles, a dry mouth, red lips, small quantities of dark urine, a red tongue with slight coating, a weak and rapid pulse, and low-grade fevers. Chinese medicine states that if there is a wasting away caused by a consumptive disease, then yin deficiency must be present. (For this reason, HIV disease is therefore often diagnosed as a yin deficiency.)