The biggest news from Michael Phelps' recent interview on "60 Minutes" wasn't that he plans to retire after the upcoming Summer Games, but that he keeps his eight gold medals from Beijing in a traveling makeup case and sleeps in a high-altitude chamber.*

[ Photos: The 2012 Olympic medals revealed ]

Phelps made the revelations to Anderson Cooper in a segment aired Sunday night. First, he showed off his gold-medal carrier:

For an extra layer of security, he stuffs the eight golds in a gray T-shirt:

He later talked to Cooper about his high-tech sleeping chamber that allows him to sleep at the equivalent of 8,500 feet above sea level.

Phelps wouldn't show the contraption to CBS cameras, but tweeted a picture of it to his fans:

The $15,000 device removes oxygen from the room. Hypoxico, the maker of the device, says on its website that its product "triggers the onset of a range of physiological adaptations geared towards enhancing the efficiency of the body's respiratory, cardiovascular and oxygen utilization systems."

Phelps spoke of the oddity of having a separate chamber in which to sleep. "Once I'm already in my room i still have to open a door to get into my bed," he told Cooper. "It's just like a giant box. It's like the boy in the bubble."

* OK, maybe it was the retirement.

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