RACHEL MARTIN, HOST:
We've been exploring the mystery of sleep this morning - how we're not getting enough of it, and why we need it in the first place.
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MARTIN: We asked our listeners to share their sleep troubles.
EMILY MCMAMEE: So I have always slept-walk and slept-talk, and it's always been amusing for everybody else around me. I learn about it the next morning, when people tell me, do - you know, did you know that you just did this?
MARTIN: Emily McMamee is from Starksboro, Vt.
MCMAMEE: We were on vacation, and so my brother and I were sleeping in bunk beds, which I don't think I had ever slept in before, and I was in the top bunk. And I had a very vivid dream of a diving competition at the local pool.
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MCMAMEE: And the next thing I know is, I dove out of the bunk bed and hit the wall - which was incredibly painful and embarrassing, and meant that I had to wear a hat for the rest of our beach vacation, to cover up my scar.
MARTIN: And here's another vexing sleep issue - this one from Jared Oliver of Akron, Ohio.
JARED OLIVER: One of the most frustrating feelings is to have undiagnosed narcolepsy. Been through a lot of occupations over the past couple of years. And I hope everything works out because it's hard enough climbing the corporate ladder without falling asleep on the way up.
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MARTIN: The riddle of Emily's sleepwalking and Jared's narcolepsy appeals to sleep scientists like Jeff Ellenbogen of Johns Hopkins Medical Center, in Baltimore.
DR. JEFF ELLENBOGEN: I'm desperate to find all that out and, you know, if I do even a fraction of that in a lifetime, I think I will have achieved something because sleep is still fundamentally a mystery.
MARTIN: Same thing for Matthew Walker, of U.C. Berkeley.
MATTHEW WALKER: There have been so many great discoveries within science based on the revolution of sort of genetics and molecular biology. And sleep remains resistant to all of that, in terms of an answer. So it's a fantastically complex puzzle. And as a researcher, that's what you want. You don't want something where there's an easy answer.
MARTIN: That is not the case for NPR science correspondent Joe Palca. Before Joe was a journalist, he studied psychology - even got his Ph.D. in it. He focused on sleep research, and he found it frustrating. We'll let Joe explain.
JOE PALCA, BYLINE: I got out of sleep research 31 years ago, so my knowledge is a bit dusty. I left scientific research because science journalism seemed like a much more interesting career. But I also have to say that by the time I completed my doctorate, I was feeling rather frustrated with sleep research. Although there was a wealth of knowledge about sleep, it all seemed very descriptive. We knew what brain waves looked like during sleep. We knew what hormones were released, how blood flow changed, how body temperature fluctuated. But there didn't seem to be much progress answering the really big questions: Why do we sleep? Why do our eyes dart around, and our muscles become flaccid, during rapid eye movement sleep? Why do we dream? As far as I can tell, those are all still open questions.
One thing we do know: Sleep is necessary. We quite literally can't live without it. And not getting enough sleep can make it harder to function during the day. So sleep is a need, just like the need to eat or the need to breathe. But we know why we eat and breathe. So why don't we know why we sleep?
Sometimes when it's hard to answer a question, it means you're not asking the right one. Maybe asking why we sleep is like asking why we wake. There is no why; it just is.
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PALCA: I'm glad scientists continue to pound away, searching for answers to the big questions about sleep. But I also have to say, I'm glad I'm not one of them. I like questions that I can find the answer to.
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MARTIN: NPR science correspondent Joe Palca. For more on our sleep series, go to our website, npr.org.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.