While no human being is known to have died from staying awake, animal research strongly suggests it could happen. In the 1980s, a University of Chicago researcher named Allan Rechtschaffen conducted a series of groundbreaking experiments on rats. After 32 days of total sleep deprivation, all the rats were dead. Curiously, researchers still do not agree on the cause of death. It's possible that the rats' body temperature dropped so much that they succumbed to hypothermia. Another theory posits that the rats' immune systems became so depressed that bacteria normally sequestered in their intestines spread throughout their bodiesthough Rechtschaffen counters that his rats perished even when they were administered antibiotics. A third explanation points to some evidence of brain damage among the sleep-deprived rats. It's also possible that extreme levels of stress contributed to the rats' demise.
Around a hundred prisoners died during interrogation by US forces under George W. Bush.