In the developed world,

everywhere, women live an average of six to eight years longer than men do.

Six to eight years longer.

That's, like, a huge gap.

In 2015, the "Lancet" published an article

showing that men in rich countries

are twice as likely to die as women are

at any age.

But there is one place in the world

where men live as long as women.

It's a remote, mountainous zone,

a blue zone,

where super longevity

is common to both sexes.

This is the blue zone in Sardinia,

an Italian island in the Mediterranean,

between Corsica and Tunisia,

where there are six times as many centenarians

as on the Italian mainland,

less than 200 miles away.

There are 10 times as many centenarians

as there are in North America.

It's the only place where men live as long as women.

But why?

My curiosity was piqued.

I decided to research the science and the habits of the place,

and I started with the genetic profile.

I discovered soon enough

that genes account for just 25 percent of their longevity.

The other 75 percent is lifestyle.

So what does it take to live to 100 or beyond?

What are they doing right?

What you're looking at is an aerial view of Villagrande.

It's a village at the epicenter of the blue zone

where I went to investigate this,

and as you can see, architectural beauty is not its main virtue,

density is:

tightly spaced houses,

interwoven alleys and streets.

It means that the villagers' lives constantly intersect.

And as I walked through the village,

I could feel hundreds of pairs of eyes watching me

from behind doorways and curtains,

from behind shutters.

Because like all ancient villages,

Villagrande couldn't have survived

without this structure, without its walls, without its cathedral,

without its village square,

because defense and social cohesion defined its design.

Urban priorities changed as we moved towards the industrial revolution

because infectious disease became the risk of the day.

But what about now?

Now, social isolation is the public health risk of our time.

Now, a third of the population says

they have two or fewer people to lean on.

But let's go to Villagrande now as a contrast

to meet some centenarians.

Meet Giuseppe Murinu. He's 102, a supercentenarian

and a lifelong resident of the village of Villagrande.

He was a gregarious man.

He loved to recount stories

such as how he lived like a bird

from what he could find on the forest floor

during not one but two world wars,

how he and his wife, who also lived past 100,

raised six children in a small, homey kitchen

where I interviewed him.

Here he is with his sons Angelo and Domenico,

both in their 70s and looking after their father,

and who were quite frankly very suspicious of me and my daughter

who came along with me on this research trip,

because the flip side of social cohesion

is a wariness of strangers and outsiders.

But Giuseppe, he wasn't suspicious at all.

He was a happy-go-lucky guy,

very outgoing with a positive outlook.

And I wondered: so is that what it takes to live to be 100 or beyond,

thinking positively?

Actually, no.

(Laughter)

Meet Giovanni Corrias. He's 101,

the grumpiest person I have ever met.

(Laughter)

And he put a lie to the notion

that you have to be positive to live a long life.

And there is evidence for this.

When I asked him why he lived so long,

he kind of looked at me under hooded eyelids and he growled,

"Nobody has to know my secrets."

(Laughter)

But despite being a sourpuss,

the niece who lived with him and looked after him

called him "Il Tesoro," "my treasure."

And she respected him and loved him,

and she told me, when I questioned this obvious loss of her freedom,

"You just don't understand, do you?

Looking after this man is a pleasure.

It's a huge privilege for me.

This is my heritage."

And indeed, wherever I went to interview these centenarians,

I found a kitchen party.

Here's Giovanni with his two nieces,

Maria above him

and beside him his great-niece Sara,

who came when I was there to bring fresh fruits and vegetables.

And I quickly discovered by being there

that in the blue zone, as people age,

and indeed across their lifespans,

they're always surrounded by extended family, by friends,

by neighbors, the priest, the barkeeper, the grocer.

People are always there or dropping by.

They are never left to live solitary lives.

This is unlike the rest of the developed world,

where as George Burns quipped,

"Happiness is having a large, loving, caring family in another city."

(Laughter)

Now, so far we've only met men,

long-living men, but I met women too,

and here you see Zia Teresa.

She, at over 100, taught me how to make the local specialty,

which is called culurgiones,

which are these large pasta pockets

like ravioli about this size,

this size,

and they're filled with high-fat ricotta and mint

and drenched in tomato sauce.

And she showed me how to make just the right crimp

so they wouldn't open,

and she makes them with her daughters every Sunday

and distributes them by the dozens to neighbors and friends.

And that's when I discovered a low-fat, gluten-free diet

is not what it takes to live to 100 in the blue zone.

(Applause)

Now, these centenarians' stories along with the science that underpins them

prompted me to ask myself some questions too,

such as, when am I going to die and how can I put that day off?

And as you will see, the answer is not what we expect.

Julianne Holt-Lunstad is a researcher at Brigham Young University

and she addressed this very question

in a series of studies

of tens of thousands of middle aged people

much like this audience here.

And she looked at every aspect of their lifestyle:

their diet, their exercise,

their marital status,

how often they went to the doctor,

whether they smoked or drank, etc.

She recorded all of this

and then she and her colleagues sat tight and waited for seven years

to see who would still be breathing.

And of the people left standing,

what reduced their chances of dying the most?

That was her question.

So let's now look at her data in summary,

going from the least powerful predictor to the strongest.

OK?

So clean air, which is great,

it doesn't predict how long you will live.

Whether you have your hypertension treated

is good.

Still not a strong predictor.

Whether you're lean or overweight, you can stop feeling guilty about this,

because it's only in third place.

How much exercise you get is next,

still only a moderate predictor.

Whether you've had a cardiac event and you're in rehab and exercising,

getting higher now.

Whether you've had a flu vaccine.

Did anybody here know

that having a flu vaccine protects you more than doing exercise?

Whether you were drinking and quit,

or whether you're a moderate drinker,

whether you don't smoke, or if you did, whether you quit,

and getting towards the top predictors

are two features of your social life.

First, your close relationships.

These are the people that you can call on for a loan

if you need money suddenly,

who will call the doctor if you're not feeling well

or who will take you to the hospital,

or who will sit with you if you're having an existential crisis,

if you're in despair.

Those people, that little clutch of people

are a strong predictor, if you have them, of how long you'll live.

And then something that surprised me,

something that's called social integration.

This means how much you interact with people

as you move through your day.

How many people do you talk to?

And these mean both your weak and your strong bonds,

so not just the people you're really close to,

who mean a lot to you,

but, like, do you talk to the guy who every day makes you your coffee?

Do you talk to the postman?

Do you talk to the woman who walks by your house every day with her dog?

Do you play bridge or poker, have a book club?

Those interactions are one of the strongest predictors

of how long you'll live.

Now, this leads me to the next question:

if we now spend more time online than on any other activity,

including sleeping,

we're now up to 11 hours a day,

one hour more than last year, by the way,

does it make a difference?

Why distinguish between interacting in person

and interacting via social media?

Is it the same thing as being there

if you're in contact constantly with your kids through text, for example?

Well, the short answer to the question is no,

it's not the same thing.

Face-to-face contact releases a whole cascade of neurotransmitters,

and like a vaccine, they protect you now in the present

and well into the future.

So simply making eye contact with somebody,

shaking hands, giving somebody a high-five

is enough to release oxytocin,

which increases your level of trust

and it lowers your cortisol levels.

So it lowers your stress.

And dopamine is generated, which gives us a little high

and it kills pain.

It's like a naturally produced morphine.

Now, all of this passes under our conscious radar,

which is why we conflate online activity with the real thing.

But we do have evidence now, fresh evidence,

that there is a difference.

So let's look at some of the neuroscience.

Elizabeth Redcay, a neuroscientist at the University of Maryland,

tried to map the difference

between what goes on in our brains when we interact in person

versus when we're watching something that's static.

And what she did was she compared the brain function

of two groups of people,

those interacting live with her

or with one of her research associates

in a dynamic conversation,

and she compared that to the brain activity of people

who were watching her talk about the same subject

but in a canned video, like on YouTube.

And by the way, if you want to know

how she fit two people in an MRI scanner at the same time,

talk to me later.

So what's the difference?

This is your brain on real social interaction.

What you're seeing is the difference in brain activity

between interacting in person and taking in static content.

In orange, you see the brain areas that are associated with attention,

social intelligence --

that means anticipating what somebody else is thinking

and feeling and planning --