Stefania Follini

Stefania Follini was a woman who, in a 1989 experiment on circadian rhythms, voluntarily isolated herself for four months in an underground room fifty feet down a cave in Carlsbad, New Mexico, away from all outside indications of night and day.

Inside her twenty by twelve foot acrylic glass room, away from all cues to the normal 24-hour daily cycle, her biological clock drifted away from its regular rhythm. She started staying awake for up to forty hours and sleeping up to twenty-two hours at a time.

With her slowed-down daily cycle, her meals were more spread out and she lost weight. She reported that at one point her menstrual cycle had stopped.

When she finally emerged from the cave at the experiment's end in May, and was asked to guess the date, she estimated it was still March—only two months from the start of the experiment instead of the four that had actually transpired.