Sleep deprivation
In rats, sleep deprivation causes weight loss and reduced body temperature. Rats kept awake indefinitely develop skin lesions, hyperphagia, loss of body mass, hypothermia, and, eventually, fatal sepsis. Sleep deprivation also hinders the healing of burns on rats. When compared with a control group, sleep-deprived rats' blood tests indicated a 20% decrease in white blood cell count, a significant change in the immune system.