I honestly thought it would be much easier. Forty-eight hours without emails, phone calls or work: It sounded vaguely appealing, even.

However, it turned out to be two of the worst days of my life.

Even though the downtown Denver County Jail is one of the newest, cleanest facilities in America, being locked up in solitary confinement is extraordinarily uncomfortable.

The worst part is the screaming. The sounds of my fellow inmates losing their minds was incredibly unsettling.

Then, there's the cold, the barely edible food, the fact that the lights never go out for security reasons, the total lack of privacy and - worst of all - the sheer boredom. I spent my time pacing, doing push-ups and reading tattered detective novels from the tiny jail library.

If 48 hours was difficult for me, I can't imagine how it is for the estimated 80,000 men and women involuntarily locked up in solitary every day in America.

We can all agree that people who commit crimes need to be punished, but critics say solitary is "legalized torture" that makes inmates more likely to reoffend and can also cost three times as much as regular inmate housing.

The issue has become increasingly controversial - the subject of congressional hearings, United Nations reports and inmate hunger strikes. Corrections officials argue that, despite its drawbacks, solitary confinement is a necessary tool to control a dangerous population.

To get a sense of what it's really like, I made myself an inmate for two days. You can see the results tonight on "Nightline."

A special thanks to the American Friends Service Committee for special footage of solitary confinement.