How long can a human stay awake, and what happens along the way?

The best-documented answer is Randy Gardner's: 11 days and 25 minutes, or 264.4 hours, in December 1963 and January 1964. He was 17, and he broke the previous record of 260 hours. Longer stunts have been reported since. The Guinness record was set in 1977 by Maureen Weston, after presumably staying awake for 449 hours in a rocking-chair marathon. But records for voluntary sleep deprivation are a murky business, for two reasons: Guinness stopped accepting attempts in 1997 for safety reasons, and it is hard to verify a long wakeathon unless the person is watched for short microsleeps, which they might not even notice.

Gardner's case stands out because it was so carefully documented. Stanford sleep researcher William Dement attended, and Navy officer John Ross monitored his health. Dement reported that on the tenth day Gardner beat him at pinball, and the story spread that extreme sleep deprivation has little effect. Ross reported otherwise: serious cognitive and behavioural changes, including moodiness, problems with concentration and short-term memory, paranoia and hallucinations. On day eleven, asked to subtract seven repeatedly from 100, Gardner stopped at 65 and said he had forgotten what he was doing.

Gardner appeared to recover fully. He slept 14 hours and 46 minutes at first, and sleep recordings taken one, six and ten weeks later showed no significant differences. Decades later, in 2017, he reported serious insomnia that began around 2007, and believed his participation in the 1960s study was to blame.

Radio host Peter Tripp, in 1959, was less lucky. He stayed awake for 201 hours, began to hallucinate after a few days, and afterwards began to think he was an imposter of himself.