Studies have shown that over time, most humans need eight to eight and a half hours of sleep for the best health.

VOA: special.2009.08.26

And if they do not have a traditional coffin to sleep in during the day, they can find other answers, such as using a car.

VOA: special.2010.01.20

"I actually have them sign a form saying you will be running, you will skip meals, you will not get sleep."

VOA: standard.2010.02.26