Russian researchers in the late 1940s retained five people awake for a fortnight using a trial gas based stimulant.
They were kept in a vacuum-packed environment to carefully monitor their oxygen consumption so the gas didn’t kill them, since it was poisonous in high concentrations. This was before closed circuit cameras so they had only microphones and 5 inch thick glass aperture sized windows into the chamber to monitor them.
The chamber was supplied with books, cradles to sleep on but no bedding, running water and toilet, and adequate dried food to last all five for over a month.
The test subjects were governmental prisoners supposed enemies of the state during World War II.