One of a professional's most important daily rituals is how and when they sleep, since this affects how well they perform on the job.
For people at the top, who often face intense pressure and packed schedules, sometimes these sleeping habits can be quite strange.
Olympic gold medalist Michael Phelps, for instance, sleeps in a high altitude chamber which forces his body to work even while resting. Meanwhile, famed writer Charles Dickens always slept facing north, and inventor Nikola Tesla never slept for more than two hours a night.
Here's a look at the most bizarre sleeping habits of highly successful people.
Tom Cruise sleeps in a sound-proof 'snoratorium.'
Cruise's snores are apparently so bad, he sleeps in a sound-proof "snoratorium."
"Whoever uses the snoring room cannot be heard outside the locked door," an alleged visitor to the actor's house told the Daily Mail. "It's very small, comfortable and dark, maybe a former nursery."
Winston Churchill took a two-hour nap every day.
Every day at 5 p.m., the prime minister would drink a weak whisky and soda before taking a nap for nearly two hours. Churchill said this "siesta," or short nap, allowed him to get one and a half day's worth of work out of every 24 hours.
Churchill was known to be a night owl and would often work through the night. Due to his irregular sleep schedule, he was said to hold War Cabinet meetings in his bath.
Mariah Carey surrounds her bed with 20 humidifiers and needs 15 hours of shut-eye per night.
"I've got to sleep 15 hours to sing the way I want to,"Carey told Interview magazine in 2007. She also admitted to sleeping with 20 humidifiers around her bed.
"Basically, it's like sleeping in a steam room," she said.
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