Doctor Answers Longevity Questions

I'm Dan Belsky.

I'm a professor of epidemiology at Columbia University.

I'm here to answer your questions from the internet.

This is Longevity Support.

[upbeat music]

sgdynol asks: Correlation between

looking young and longevity?

We know that when we show images of people

to research participants

or just raters on the internet,

how old they guess a person is

does correlate with other signs

of their health and longevity.

There was a famous study a number of years ago

by the Danish demographer Kaare Christensen

that compared the faces of older female twins.

The raters of these faces were reliably able

to pick the identical twin who was going to live longer

based on which face looked older.

Expeditio asks: Is it possible to halt aging,

and will it be in our lifetimes?

Depends on who you ask.

Some people believe fervently

that they can stop or even reverse the aging process

and that this innovation or this breakthrough

is just around the corner.

I tend to take a more conservative view of things.

I'm not sure we'll ever be able to stop aging.

My hope is that we will be able to meaningfully slow it down

in ways that give more of us more healthy years of life.

And I expect that we will see breakthroughs

that can deliver at least some extension

in healthy lifespan within the next decade.

katarinadrcelic asks: Tell me then,

without saying anything misogynist,

how do men and women age differently?

Well, I guess the first thing I'd say

is men tend to die sooner.

We have some indication

that earlier timing of death for men

is a reflection of an accelerated process

of biological aging,

molecular changes that occur

within and between our cells

maybe proceeding a little bit faster in men than in women.

But there are other evidence showing that,

particularly around menopause perhaps,

women experience an acceleration in aging relative to men.

What we do know is that men and women's bodies

change in different ways as they grow older.

And if you're trying to monitor your own aging,

you'll wanna be comparing yourself

to an appropriate reference.

OneFuzzyBlueberry asks: Fasting and longevity?

We've known for about a hundred years

that feeding mice less makes them live longer.

With the caveat that,

when we talk about caloric restriction or fasting

in the context of healthy longevity research,

we're talking about reducing total calorie intake

with maintenance of what we call micronutrient sufficiency.

So we're not inducing malnutrition,

we're not doing starvation.

That said, if you can do that,

we think that either long-term reduction in caloric intake

or periodic fasting,

which is what the questioner is asking about,

can induce changes in our physiology and our biology

in ways that promote healthy longevity.

And a very simple explanation of what's going on

when we reduce the nutrient input into our system

is: we get more efficient.

Our cells start scavenging for junk, for spare parts

that they can use to keep going.

And that garbage cleanup process

turns out to be pretty good for us at the cellular level

and ultimately at the level of our lifespans.

flopsyplum asks: Why don't athletes,

who have optimal exercise and nutrition,

live longer than average people?

So it's absolutely true that exercise is good for you,

and the healthy lifestyle that many athletes enjoy

with customized diet nutrition

can promote healthy longevity.

But athletes also put their bodies under intense stress.

And there's an idea in the field of toxicology

called the hormesis curve

that describes how the dose of a stressor

corresponds to its impact on your health.

And there are some things like exercise

where some of a thing can be good for you,

is health-enhancing.

When you lift weights, you tear your muscles

and they heal back stronger than they were beforehand.

That's hormetic.

But if you put too much stress on a system,

you can induce lasting damage.

And for many athletes

who are trying to operate at the margins of human capacity,

they may be ending up

on the wrong side of that hormesis curve.

scgbhg asks: Does exercise increase your longevity?

And if so, by how much?

Exercise is as close a thing

to a molecular fountain of youth as we have found.

It is good for literally all of us.

In terms of how much it can increase your lifespan,

it's gonna vary from person to person.

And the particular kind of exercise

that's gonna be most beneficial

is probably different for you than it is for me.

kaiser9798 asks: I'm getting old...

Why do all my joints hurt now?

I didn't do nothing to warrant the pain.

So the reason your joints hurt when you get old

is that the tissues that cushion them shrink,

and that leads to more bone-on-bone contact to some extent

and will cause pain.

You see an upregulation of inflammation

as we grow older.

When the joints get inflamed, that will cause pain.

But it is in some sense your fault

insofar as it's the wear and tear we put on our bodies

that causes them to age faster or slower.

And so if you are feeling it as you're getting older,

it's some combination of the genetics you were born with

and the way you've lived your life.

jihaneelachqar asks: Why do we age?

Why do we grow old and die?

And how does the world really work?

I'm gonna do two out of three.

We age because evolution doesn't care what happens to us

after a certain point.

Our biology is engineered

to grow us into organisms that can reproduce,

maybe care for our young for a little while,

and then after that, meh.

So as a result, the various mechanisms in our body

that fight off the damage that the world causes

to our cells day in and day out

are less effective after a certain point of time.

They're not maintained forever.

And that's what ultimately allows our bodies

to break down as we grow older.

Now, what actually causes us to grow old and die

is, we think, an accumulation of molecular damage,

damage that occurs to our cells and the DNA

and the other contents inside them

that our bodies are progressively less able to repair

as we move on in life.

And that accumulation of damage

ultimately disregulates a wide range

of different biological processes,

leading our organs to fail, our tissues to fail.

We get sick, we become frail,

we lose functional capacity, and eventually we die.

carly_solstice asks: Does the aging process

just go to warp speed as you approach 40?

I feel like my gray hairs have quadrupled

and my wrinkles madly increased

in just the last few months.

So we don't know exactly

what the dynamics of human aging look like,

but we have some interesting signs

that there are periods in our life when aging speeds up

and others when it may slow down a little bit.

A recent study at Stanford

that tracked several dozen people

over a period of a couple of years

and compared how their bodies were changing

observed signs that the aging process

really does experience these points of acceleration

around the transition to midlife, maybe 30s to 40s,

and then again later in your 60s.

For any given person,

those inflection points may happen

a little earlier or a little later.

But we are starting to learn

that aging is not a linear process

and it's not purely one that just gets faster over time.

Yoyogogobop asks: Is the whole Blue Zone thing legit?

Something feels off.

Blue Zones are places that are characterized

by exceptional longevity.

They're places where a lot of people

get to live a very long time, maybe 100, maybe 105.

But to say first: the Blue Zone thing is legit

insofar as the way people live

and the kinds of places they live in

are deeply consequential for how long they live

and how much health they get to live with.

And the things that have come out of the Blue Zone story,

eating a healthy diet, not too much,

plenty of physical activity, lots of social connection,

these things are absolutely good for us

and they do help us age more slowly or with more health

and live longer lives.

On the other hand,

it turns out that some of the reasons

particular places get identified as Blue Zones

has more to do with the quality of their record keeping

than the lives of the citizens who lived there.

And what I mean by this is that, a long time ago,

different places were better or worse at keeping records

of when people were born.

In places where those records were of lower quality,

were sometimes destroyed or were lost,

people would manipulate the year of birth

because they wanted to join the army,

because they wanted to get a job,

because they wanted to get married.

And many decades later,

that can turn somebody who died at 85

into somebody who died at 100 or even older than that.

And so there is a systematic relationship

between the quality of record keeping

and the likelihood that your particular area

will be designated a Blue Zone.

But it doesn't take anything away from the central insight

of the Blue Zone narrative,

which is about how the ways we live can have a big impact

on how long we live and how much health we get to live with.

Sairira asks: Is aging a disease?

Oof, this is a contentious question

with big money behind it.

And the reason is that agencies

like the U.S. Food and Drug Administration

that have to approve clinical trials

will only let you develop drugs if they treat a disease.

Right now aging is not a disease,

and so it's proven very challenging to design therapies

to slow it down or dial it back

and to test them in the gold standard method that we use

to evaluate other kinds of medicines.

For this reason and because it does things to us

that we want to prevent,

people have argued that aging

should be reclassified as a disease.

On the other hand, aging is something we all do.

It's a normal part of life.

And others argue that, as a result,

we shouldn't think of it as a disease

and we shouldn't try to stop it.

I think in some ways it doesn't really matter

whether we call it a disease or not.

It's a process that we go through.

We'd like to experience it a little more slowly,

maybe a little later in life,

and we think that it's reasonable

to try and develop interventions to achieve that goal.

And I think we'll see that in the years ahead.

dystopian_manure asks:

What is the potential maximum human life expectancy?

We don't know.

There are lots of ways of asking this question:

how long can a human live?

The one that has made the news most recently

was a comparison of the oldest person in the world

over a long period of time, more than a hundred years.

They were able to collate records

and compare how old the longest lived person was

each year until today.

So as far as we know, the oldest person ever

was a woman in France, Jeanne Calment,

who lived to 122 years old.

She smoked for most of her lifetime.

She had a lot of chocolate, she drank red wine.

She made it look pretty good.

Since then, the longest lived person

has always been younger than that.

And that has invited the idea

that maybe this is the natural peak of human lifespan.

There are reasons to believe there is some kind of limit,

but whether we've reached it

or whether it's close to where we are today,

I think we still don't know.

Calamaja asks: Why do people seem to age so incredibly fast

after a traumatic experience?

So this is a great question.

Stress kills us,

and it kills us in lots of different ways,

partly because it triggers a physiological response

that is designed to help us.

What we need for fight or flight

when we find ourselves in a high-stress situation

50,000 years ago,

there's like a saber-tooth tiger chasing us

or something like that,

and what we need today

when our boss is yelling at us at work

are not the same thing.

But evolution doesn't know that.

And so when we experience extreme stress,

our body ramps up an inflammatory and metabolic response

designed to give us a lot of available energy

and to fight off infections that we might sustain

when we get bitten or stabbed or otherwise injured.

Those processes, when chronically activated,

cause wear and tear on our bodily systems

in ways that make us more vulnerable to disease.

The neuroscientist Bruce McEwen

called this process allostatic load

or the load that's involved in bringing our body back

from that wild state

to a kind of homeostasis or rest state.

We see signs of this in lots of places.

And recently there were some fascinating experiments

done in animals and also human surgical patients

showing that what we can estimate

from people's DNA about how fast they're aging

suggests that aging speeds up

when we get one of these traumatic stressors like a surgery

and it can slow down afterwards.

We also of course see that people who live lives

characterized by higher levels of chronic stress

age more rapidly,

onset with disease at younger ages, and die sooner.

GrantDixonMD asks: You ever think about

how 100 years ago doctors told people not to exercise

'cause it would shorten their heart's lifespan

and wonder what advice we, doctors, are giving now

that in 100 years people will look back on

and say, 'Wow, how stupid was that?'?

We don't have to go back a hundred years.

When I was a kid, we were not supposed to eat any fat.

And now we know that was terrible advice.

I think there are undoubtedly

all kinds of medical advice that we get today

that will be looked back on in the future as a bad idea.

But when I think about things that have a short lifespan

in terms of their received wisdom,

it's gonna be fad diets, particular exercise regimes,

and, in general, the idea that any specific program

of behavior change, nutritional supplementation

or whether it's cryotherapy or cold plunges,

is gonna be good for everyone.

What we're learning today in medicine

is that every patient

is their own particular medical challenge

and that the optimal therapy we can deliver

is gonna be tailored to that person's genetics,

to their microbiome, to their life history.

And as we move into the future,

I think medicine is going to be better at learning

what makes us different from each other

and tailoring therapies to each of us individually

to achieve better results.

A Reddit user asks: Which longevity treatment

will be the first to go mainstream?

Well, I think, you know,

healthy diet and exercise are pretty mainstream.

They've been with us for an awfully long time.

Caloric restriction or intermittent fasting,

those are also ancient practices.

And so those are sort of mainstream now.

But if you think about what's new that's gonna happen,

I think we're gonna see, within the next decade,

medicines that are already prescribed today

being repurposed as agents to slow aging.

And I'm not gonna take any bets

on exactly which of those drugs

are gonna break through first,

but I suspect it will be from a category

that is now used to treat diabetes

and metabolic dysregulation.

un_H-nu asks: Do we have evidence

that inflammation drives aging?

So inflammation is a biological process,

and it's one that we need.

So it's not all bad.

There are things our body wants to get rid of,

and inflammation helps us do that.

But too much of it can cause damage to our cells and tissues

in ways that can accelerate the aging process.

Inflammation can be caused by diseases,

it can also be a cause of diseases,

but it's definitely a mediator of the aging process.

searchingforlife asks:

Do those who sleep for longer intervals live longer lives?

There is epidemiological evidence

linking the right amount of sleep to a longer lifespan.

Sleep is kind of like a Goldilocks thing.

You don't sleep enough, you're gonna die sooner.

You sleep too much, you're also gonna die sooner.

But that's not necessarily cause and effect.

That's just correlation when we survey people

about how much they sleep

and we correlate that with how long they live.

And we suspect that one of the reasons,

for example, shorter sleep duration

may be associated with shorter lifespan

is that people who are sleeping less

are often engaging in other behaviors

that may be health-damaging,

whether it's working too hard

or drinking and smoking too much

or living in chaotic environments.

On the other hand,

people who are sleeping a very long time may be doing so

because they already have chronic diseases

that are shortening their lifespan.

That said, we do have some evidence

that achieving the right kind of sleep

and a decent amount of it

is good for our biology in ways

that could be positive for slowing the aging process

and preserving healthy lifespan.

IanYeo asks: What is the impact of meditation

on aging of the brain?

We don't know for sure

that meditation will keep us healthy for longer,

but we have some very positive signs.

And we think that the reason meditation

has benefits for our brain health

and the health of the rest of our body

is that it helps us manage stress.

It calms us down.

It allows us to connect

with meaning and purpose in our lives.

And even in acute treatment phases

can show signs of downregulating processes like inflammation

that can damage tissues and organs.

We can't tell you exactly how much

meditating will slow down your aging

or even what type of meditation

will be most effective for you.

But we do have evidence

that meditative activity, finding peace in your life

can have health benefits.

Bubblebrew asks: If our telomeres never shortened,

could we live forever?

So telomeres are repeated nucleotide sequences

at the end of our chromosomes.

They're actually DNA.

And they act to protect the chromosome from damage.

And every time the cell divides,

they get a little bit shorter.

We're really excited about telomeres in aging

because the rate of telomere shortening

functions as a kind of molecular clock

for the life of a cell.

But it doesn't necessarily mean the same thing

if we measure it from a blood sample

where we're getting telomere length in thousands of cells

and across all the chromosomes in each of those cells.

As for: if we stop telomere erosion, would we stop aging?

The answer is definitely, no,

because we just get a lot of cancer.

In fact, that's what cancer is.

It's the escape from what we call replicative senescence

or the way in which dividing a lot

ultimately induces senescence and death in a cell.

So we don't wanna stop it.

And, as of today, there are no therapies that you can take

that will elongate your telomeres

in a way that will promote your health.

abundantpecking asks: Just how much of aging

can actually be prevented by sunscreen?

Sunscreen is definitely good for your skin

and it will keep you looking younger,

but I don't know that we have evidence,

other than protecting you from skin cancer,

that wearing sunscreen is particularly helpful

in slowing the aging process in your internal organs.

GuitarMartian asks: How will CRISPR help cure aging?

There are people who have the idea

that aging is caused by changes to the DNA in our cells.

And CRISPR is a way to edit DNA,

and it could be a way to reverse those changes.

But getting all the right changes made

and none of the wrong ones

is gonna be awfully challenging.

So the way that CRISPR is more likely to help cure aging

is it allows us to dramatically accelerate

the pace of research.

We can do experiments in months that used to take years

before we could edit DNA in this way.

And so CRISPR is really a game changer,

but more in the lives of scientists

than in the lives of patients.

That's it, that's all the questions.

Hope you learned something, and until next time.

[soft ethereal music]