7 Healthcast: Eight hours of sleep not a necessity for all of us

But there are a few, about 1 to 3 percent of the population, who only need a few hours.

They’re called "short sleepers," and they typically turn in after midnight and get up ahead of sunrise.

They don’t need naps or to load up on caffeine to get through the day.

The Wall Street Journal reports they tend to be energetic, optimistic and ambitious.

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