How long can a person go without sleep?

Gardner stayed awake for a school science project, and sleep researcher William Dement observed part of the attempt. Towards the end he suffered from memory lapses, mood swings, blurred vision and hallucinations. Studies show that staying awake for 17 to 19 hours can impair performance about as much as a blood alcohol level of 0.05 percent. The brain also begins slipping into microsleeps, brief lapses of a few seconds that happen without warning. Guinness World Records no longer accepts attempts at this record, because extreme sleep loss is dangerous.