How long can humans go without sleep?

The longest scientifically recorded time that a human has gone without sleep is 264 hours (11 days).

This experiment carried out by Randy Gardner and two Stanford scientists in 1965. Gardner experienced several hallucinations, cognitive impairments, and paranoia during this experiment.

Most people can go without sleep for approximately 72 hours before experiencing severe fatigue and a decline in cognitive function. However, some people can remain awake for much longer periods.