In 1965, 17 year-old high school student Randy Gardner stayed awake for 264 hours, namely 11 days, to see how he'd cope without sleep. On the second day, his eyes syopped focusing. Next, he lost the ability to identify objects by touch. He then became moody and irritated. The harms of sleep deprivation are long-lasting. Why do we sleep? Watch the video of a TED Talk for more detailed information.
Photo: screenshot of the video