RACHEL MARTIN, HOST:
So I'm going to ask you, are you a glass half full kind of guy or a glass half empty kind of guy?
STEVE INSKEEP, HOST:
I'm just happy when there's a glass.
MARTIN: You're just thirsty all the time.
INSKEEP: Give me a glass.
MARTIN: I think I'm a glass half full kind of a person.
INSKEEP: I think so too. I think so too. You can see how things can improve over time. You take the long of things.
MARTIN: This bodes well for me, and you're going to hear why because NPR's Allison Aubrey is going to tell us how optimism can help you live longer.
ALLISON AUBREY, BYLINE: Here's a quick way to determine if you're an optimist.
Are you a sort of glass half full or a glass half empty person?
STACY BARBOZA: I'm going to say half full.
AUBREY: That's Stacy Barboza (ph), a commuter I met in the train station on the way to work. She has a lot in common with some of the 70,000 women enrolled in the Nurses' Health Study that researchers at Harvard have been tracking over the last few decades.
BARBOZA: I'm always an optimist. You have to be, right? Otherwise what's the point (laughter)?
AUBREY: Researchers have found that women in the study who consistently say that they expect the best, even in uncertain, times or that they're optimistic about the future, despite the obstacles, are living longer than their pessimistic peers. Here's Harvard's Eric Kim.
ERIC KIM: When we compare people with the highest versus lowest optimism, which was the top 25 percent versus bottom 25 percent, we found that there was about a 30 percent reduction in risk of mortality.
AUBREY: The most optimistic were less likely to die prematurely from diseases including cancer and heart disease. Kaitlin Hagan, a co-author of the study, says this doesn't mean there's a simple cause and effect.
KAITLIN HAGAN: I think it's partly that more optimistic people have better diets and they exercise more often and they have better sleep quality. And we know that all of those factors are related to a lower risk of mortality.
AUBREY: But Hagan says the research also suggests there's something more at play. When they controlled for all these diet and exercise-related benefits, optimism still seem to have a positive effect. Here's Eric Kim again.
KIM: More optimistic people actually cope in better ways, which in turn reduces stress, which, in a lot of situations, can be bad for the body.
AUBREY: Researchers are learning more about how our emotional state can influence things like inflammation and blood pressure.
KIM: Optimism may actually directly impact our biology.
AUBREY: Now, if you're not a natural-born optimist, Eric Kim says it is possible to learn to be more positive.
KIM: How I like to think about it is there's a range of tools that we can use to potentially enhance our health, and there's some studies showing that you can increase optimism.
AUBREY: And Kim says one of the best ways to cultivate optimism is to practice it. The commuter I met, Stacy Barboza, says she's proof of this.
BARBOZA: Well, I didn't used to think this way when I was younger.
AUBREY: What changed?
BARBOZA: Meeting people who are always positive, you know, and saying to myself, like, I want to be like that. I want to wake up with a smile on my face and happy about just being alive.
AUBREY: Eric Kim says one thing you can do is start writing down each day what you've done to be kind and what you're grateful for. Allison Aubrey, NPR News.
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