Meet Randy Gardner: The teen who stayed awake for 11 days reveals the toll it took on his body

In 1964, 17-year-old Randy Gardner set out to challenge the limits of human endurance by staying awake for 11 days. What began as a science fair project quickly spiralled into a widely publicised experiment on human endurance and the dangers of sleep deprivation.

For the experiment, Gardner fought off sleep, and his two friends, Bruce McAllister and Joe Marciano Jr, monitored him around the clock, administering a set of cognitive and physical tests every six hours.

By day three, the effects of extreme wakefulness had started to show: trouble focusing, memory lapses, and mood swings. “About the fourth or fifth day, I was like — are you kidding me, this is hard,” Gardner recalled in a Guinness World Records video posted on YouTube. But media attention meant there was no turning back.

The experiment drew the attention of sleep researcher Dr William Dement from Stanford University, who observed the final three days. Often referred to as the father of sleep science, Dement drove Gardner around with the radio blaring and even played pinball with him to keep him alert. Shockingly, Gardner managed to win.

“Physically, I didn’t have any problems,” Gardner told NPR in a 2017 interview, according to an HT report.  He told the news outlet that his mental health took a toll.

By the end of the 264 hours- that’s 11 days and 25 minutes- Gardner was experiencing paranoia and hallucinations, a clear sign of how severely sleep deprivation can affect the brain. After the experiment, he reportedly slept for nearly 15 hours as researchers studied his physiological recovery.

Although Gardner eventually returned to a normal sleep pattern, he later revealed suffering from chronic insomnia for years, a condition he linked to the experiment.

While Randy Gardner’s record was surpassed within the same year, his 11-day sleepless stretch remains one of the most extensively studied cases of sleep deprivation. The experiment later became foundational in understanding “microsleeps”—brief, involuntary lapses into sleep that last just a few seconds, as defined by Guinness World Records.

Since then, sleep science has evolved significantly, with mounting evidence on the long-term cognitive and physiological harm caused by extreme sleep loss.

The final Guinness World Record for intentional sleep deprivation was awarded in 1986 to Robert McDonald, who stayed awake for nearly 19 days. A decade later, in 1996, the organisation officially stopped accepting entries in the category, citing the risks as too dangerous to endorse.