You're listening to Shortwave from NPR.

You come home from work, you're exhausted.

You finally get into bed and your head hits the pillow.

And then the next thing you know, your car is barely out of control on the highway.

You're going around that turn.

But you're in the back seat.

You can't reach the brakes.

At least, that's my reoccurring nightmare.

But when I told that to Michelle Carr, she wasn't phased.

That is a very common dream theme. I have it all the time as well.

I think it's just related to our physical body being, like not really receiving any sensation of the car pedal.

So the dream is like going out of control.

As a sleep scientist at the University of Montreal, her job is basically watching people sleep.

So when it comes to dreams and nightmares, she's pretty much hurt at all.

Teeth falling out or flying or finding new rooms in my house.

Michelle is the author of the new book called Nightmare Obscura.

In it, she explores the science of dreams, nightmares, even something called dream engineering,

where people are able to influence their own dreams while they sleep.

But why we dream or get nightmares is still a bit mysterious for scientists.

We know so much about how important sleep is for our health,

but we're only just beginning to uncover whether dreaming

and the way that we feel during sleep is significant in our health as well.

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