NBR's editorial independence and integrity is non-negotiable.

It's the reason why so many listen to 1A's Friday News Roundup.

You'll get analysis and insight from the world's best correspondence.

Listen to 1A's Friday News Roundup Life Kit from NPR.

I'm Regina Barbara filling in from Mary El Segara.

If you're lucky enough to have traveled several time zones in a matter of hours,

then you've most likely experienced jet lag, feeling groggy, out of sync with your surroundings,

and overall crappy. This year Taylor Swift caused a stir for answering a question

after the Super Bowl about her flight on a private jet no less from Tokyo to Las Vegas

after she performed. When asked how do you not have jet lag right now?

She said, maybe jokingly,

jet lag is a choice.

She is very wrong in this instance because Jetlike is very real. It's not a choice, it's very biologically ingrained.

That's Jade Wu. A behavioral sleep medicine psychologist and researcher at Duke University School of Medicine.

I asked her to tell me what jet lag actually is.

Circadian misalignment is an umbrella term for any time your body clock is out of sync with the clock on the wall or solar clock, which is like where the sun is basically in the sky. So jet lag is one form of it. Shift work is another form,

you know, being an extreme night owl some days of the week is another form, jet-leg is just the easiest to understand form of

circadian misalignment.

Even though world travel is nothing new, the speed in which humans travel across the world has

drastically changed in the last hundred years.

We haven't evolved fast enough to keep up.

Our bodies are constantly trying to adapt to our outside environment.

...