I'm Steve Strogatz, and this is The Joy of Why.

A podcast from Quantum Magazine that takes you into some of the biggest unanswered questions in science and mathematics today.

Today, we're going to be talking all about sleep.

Why do we sleep anyway?

We spend about a third of our lives asleep, so it seems like it must be pretty important,

but there's still so much about it that we don't understand.

One thing that sleep researchers are pretty sure of is that every system in our body seems to be impacted by sleep.

When we miss out on sleep, it impairs our circulation, our digestion,

immune system, metabolism, and of course, brain function. And sleep deprivation doesn't need to

be long term to do damage. In fact, if you go without sleep long enough, you will die. But why exactly? Draganet Roggellya knows something about that.

We'll be talking with her in a minute. She's an associate professor of neurobiology at Harvard Medical School.

She studies why we need to sleep and how the brain switches between being asleep and being awake. She also looks at the lethal effects of sleep deficiencies.

Later, we'll be hearing from Alex Keene of Texas A&M University

who studies the neural regulation of sleep

and the role it plays in the bigger picture of how sleep has evolved.

He does that by looking in an unexpected place, in fish that live in caves

in Mexico. But first, Draganat Roglia, thank you so much for joining us today.

Thank you so much for inviting me. This is incredible. Yeah, I'm super excited to talk to you

about your work. But first, I was hoping we could talk broadly about sleep in general.

Like, we all understand that, you know, like I remember asking my mother, why do I have to go to

sleep when I was a little kid? And she said, well, because you're tired. It's going to help you

get rest. But sleep seems like something really different than just mere rest.

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