- 7 months ago
Dr. Dan Belsky joins WIRED to answer the internet's burning questions about longevity and epidemiology. Why do we grow old and die? Could a "cure" for aging be discovered in our lifetime? Which longevity treatment will be the first to go mainstream? Does exercise increase longevity? How about more sleep? What is the upper limit of human life expectancy? Could we possibly live forever? Answers to these questions and many others await on Longevity Support.
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00:00I'm Dan Belsky. I'm a professor of epidemiology at Columbia University.
00:04I'm here to answer your questions from the internet. This is Longevity Support.
00:11SGD Wynall asks,
00:13Correlation between looking young and longevity.
00:16We know that when we show images of people to research participants or just raters on the internet,
00:23how old they guess a person is does correlate with other signs of their health and longevity.
00:28There was a famous study a number of years ago by the Danish demographer Cor Christensen
00:32that compared the faces of older female twins.
00:37The raters of these faces were reliably able to pick the identical twin who was going to live longer
00:43based on which face looked older.
00:46Expedito asks,
00:47Depends on who you ask.
00:52Some people believe fervently that they can stop or even reverse the aging process
00:57and that this innovation or this breakthrough is just around the corner.
01:00I tend to take a more conservative view of things.
01:03I'm not sure we'll ever be able to stop aging.
01:05My hope is that we will be able to meaningfully slow it down in ways that give more of us
01:10more healthy years of life.
01:12And I expect that we will see breakthroughs that can deliver at least some extension in healthy lifespan
01:16within the next decade.
01:18Katarina Dr. Selick asks,
01:21Tell me then, without saying anything misogynist, how do men and women age differently?
01:27Well, I guess the first thing I'd say is men tend to die sooner.
01:29We have some indication that that earlier timing of death for men is a reflection of an accelerated
01:35process of biological aging.
01:38Molecular changes that occur within and between our cells may be proceeding a little bit faster
01:43in men than in women.
01:44But there are other evidence showing that, particularly around menopause perhaps, women
01:49experience an acceleration in aging relative to men.
01:52What we do know is that men and women's bodies change in different ways as they grow older.
01:56And if you're trying to monitor your own aging, you'll want to be comparing yourself to an
02:00appropriate reference.
02:02One Fuzzy Blueberry asks,
02:03Fasting and longevity?
02:06We've known for about 100 years that feeding mice less makes them live longer.
02:12With the caveat that when we talk about caloric restriction or fasting in the context of healthy
02:18longevity research, we're talking about reducing total calorie intake with maintenance of what
02:24we call micronutrient sufficiency.
02:26So we're not inducing malnutrition.
02:28We're not doing starvation.
02:29That said, if you can do that, we think that either long-term reduction in caloric intake
02:36or periodic fasting, which is what the questioner is asking about, can induce changes in our
02:42physiology and our biology in ways that promote healthy longevity.
02:46And a very simple explanation of what's going on when we reduce the nutrient input into our
02:52system is we get more efficient.
02:55Our cells start scavenging for junk, for spare parts that they can use to keep going.
03:00And that garbage cleanup process turns out to be pretty good for us at the cellular level
03:04and ultimately at the level of our lifespans.
03:07Flopsy Plum asks,
03:09Why don't athletes who have optimal exercise and nutrition live longer than average people?
03:14So it's absolutely true that exercise is good for you.
03:17And the healthy lifestyle that many athletes enjoy with customized diet and nutrition can promote
03:23healthy longevity.
03:24But athletes also put their bodies under intense stress.
03:27And there's an idea in the field of toxicology called the hormesis curve that describes how the dose of a stressor
03:34corresponds to its impact on your health.
03:37And there's some things like exercise where some of a thing can be good for you is health enhancing.
03:42When you lift weights, you tear your muscles and they heal back stronger than they were beforehand.
03:47That's hormetic.
03:49But if you put too much stress on a system, you can induce lasting damage.
03:52And for many athletes who are trying to operate at the margins of human capacity,
03:56they may be ending up on the wrong side of that hormesis curve.
03:59SCGBHG asks,
04:01Does exercise increase your longevity?
04:03And if so, by how much?
04:05Exercise is as close a thing to a molecular fountain of youth as we have found.
04:10It is good for literally all of us.
04:13In terms of how much it can increase your lifespan,
04:16it's going to vary from person to person.
04:17And the particular kind of exercise that's going to be most beneficial
04:20is probably different for you than it is for me.
04:23Kaiser9798 asks,
04:25I'm getting old.
04:26Why do all my joints hurt now?
04:27I didn't do nothing to warrant the pain.
04:30So the reason your joints hurt when you get old is that the tissues that cushion them shrink.
04:35And that leads to more bone-on-bone contact to some extent and will cause pain.
04:41You see an upregulation of inflammation as we grow older.
04:45When the joints get inflamed, that will cause pain.
04:47But it is, in some sense, your fault insofar as it's the wear and tear we put on our bodies
04:52that causes them to age faster or slower.
04:54And so if you're feeling it as you're getting older,
04:56it's some combination of the genetics you were born with and the way you've lived your life.
05:00Jahani LaCarr asks,
05:02Why do we age?
05:03Why do we grow old and die?
05:04And how does the world really work?
05:06I'm going to do two out of three.
05:08We age because evolution doesn't care what happens to us after a certain point.
05:14Our biology is engineered to grow us into organisms that can reproduce,
05:19maybe care for our young for a little while,
05:21and then after that, meh.
05:23So as a result, the various mechanisms in our body that fight off the damage
05:28that the world causes to our cells day in and day out
05:30are less effective after a certain point of time.
05:33They're not maintained forever.
05:34And that's what ultimately allows our bodies to break down as we grow older.
05:39Now, what actually causes us to grow old and die
05:41is, we think, an accumulation of molecular damage,
05:46damage that occurs to our cells and the DNA and the other contents inside them
05:51that our bodies are progressively less able to repair as we move on in life.
05:55And that accumulation of damage ultimately dysregulates
05:58a wide range of different biological processes,
06:01leading our organs to fail, our tissues to fail.
06:04We get sick, we become frail, we lose functional capacity, and eventually we die.
06:09So, we don't know exactly what the dynamics of human aging look like,
06:23but we have some interesting signs that there are periods in our life
06:26when aging speeds up and others when it may slow down a little bit.
06:29A recent study at Stanford that tracked several dozen people
06:32over a period of a couple of years
06:34and compared how their bodies were changing
06:36observed signs that the aging process really does experience
06:40these points of acceleration around the transition to midlife,
06:43maybe 30s to 40s, and then again later in your 60s.
06:47For any given person, those inflection points may happen
06:50a little earlier or a little later,
06:52but we are starting to learn that aging is not a linear process,
06:55and it's not purely one that just gets faster over time.
06:58Yogogogobop asks,
07:00Is the whole blue zone thing legit?
07:02Something feels off.
07:04Blue zones are places that are characterized by exceptional longevity.
07:08They're places where a lot of people get to live a very long time,
07:12maybe 100, maybe 105.
07:13But to say first, the blue zone thing is legit insofar as
07:17the way people live and the kinds of places they live in
07:20are deeply consequential for how long they live
07:22and how much health they get to live with.
07:24And the things that have come out of the blue zone story,
07:27eating a healthy diet, not too much,
07:30plenty of physical activity, lots of social connection,
07:33these things are absolutely good for us
07:35and they do help us age more slowly
07:38or with more health and live longer lives.
07:40On the other hand, it turns out that some of the reasons
07:43particular places get identified as blue zones
07:45has more to do with the quality of their record keeping
07:48than the lives of the citizens who live there.
07:51And what I mean by this is that a long time ago,
07:54different places were better or worse at keeping records of when people were born.
07:57In places where those records were of lower quality,
08:00were sometimes destroyed or were lost,
08:03people would manipulate the year of birth
08:05because they wanted to join the army,
08:06because they wanted to get a job,
08:08because they wanted to get married.
08:09And many decades later,
08:11that can turn somebody who died at 85
08:12into somebody who died at 100 or even older than that.
08:15And so there is a systematic relationship
08:17between the quality of record keeping
08:18and the likelihood that your particular area
08:20will be designated a blue zone.
08:22But it doesn't take anything away
08:23from the central insight of the blue zone narrative,
08:25which is about how the ways we live
08:27can have a big impact on how long we live
08:30and how much health we get to live with.
08:32This is a contentious question with big money behind it.
08:41And the reason is that agencies
08:43like the U.S. Food and Drug Administration
08:45that have to approve clinical trials
08:47will only let you develop drugs if they treat a disease.
08:51Right now, aging is not a disease.
08:53And so it's proven very challenging
08:54to design therapies to slow it down or dial it back
08:58and to test them in the gold standard method
09:01that we use to evaluate other kinds of medicines.
09:04For this reason,
09:05and because it does things to us that we want to prevent,
09:08people have argued that aging
09:09should be reclassified as a disease.
09:11On the other hand, aging is something we all do.
09:14It's a normal part of life.
09:16And others argue that as a result,
09:18we shouldn't think of it as a disease
09:19and we shouldn't try to stop it.
09:21I think in some ways,
09:22it doesn't really matter
09:23whether we call it a disease or not.
09:24It's a process that we go through.
09:26We'd like to experience it a little more slowly,
09:29maybe a little later in life.
09:30And we think that it's reasonable
09:32to try and develop interventions to achieve that goal.
09:35And I think we'll see that in the years ahead.
09:37Dystopia Manure asks,
09:38what is the potential maximum human life expectancy?
09:41We don't know.
09:42There are lots of ways of asking this question,
09:44how long can a human live?
09:45The one that has made the news most recently
09:47was a comparison of the oldest person in the world
09:50over a long period of time,
09:53more than a hundred years,
09:54they were able to collate records
09:55and compare how old the longest lived person was
09:58each year until today.
10:00So as far as we know,
10:01the oldest person ever was a woman in France,
10:04Jean Calment, who lived to 122 years old.
10:06She smoked for most of her lifetime.
10:08She had a lot of chocolate.
10:08She drank wet wine.
10:09She made it look pretty good.
10:10Since then,
10:11the longest lived person
10:12has always been younger than that.
10:13And that has invited the idea
10:15that maybe this is the natural peak of human lifespan.
10:19There are reasons to believe
10:19there is some kind of limit,
10:21but whether we've reached it
10:23or whether it's close to where we are today,
10:25I think we still don't know.
10:26Kalamaja asks,
10:27why do people seem to age so incredibly fast
10:29after a traumatic experience?
10:31So this is a great question.
10:33Stress kills us.
10:34And it kills us in lots of different ways.
10:36Partly because it triggers a physiological response
10:39that is designed to help us.
10:42What we need for fight or flight
10:43when we find ourselves in a high-stress situation
10:4650,000 years ago,
10:48there's like a saber-toothed tiger chasing us
10:49or something like that.
10:50And what we need today
10:51when our boss is yelling at us at work
10:53are not the same thing.
10:54But evolution doesn't know that.
10:56And so when we experience extreme stress,
10:59our body ramps up an inflammatory
11:00and metabolic response
11:02designed to give us a lot of available energy
11:04and to fight off infections
11:06that we might sustain
11:07when we get bitten or stabbed
11:09or otherwise injured.
11:10Those processes,
11:11when chronically activated,
11:12cause wear and tear
11:13on our bodily systems
11:15in ways that make us
11:16more vulnerable to disease.
11:17The neuroscientist Bruce McKeown
11:19called this process allostatic load
11:21or the load that's involved
11:23in bringing our body back
11:24from that wild state
11:26to a kind of homeostasis or rest state.
11:30We see signs of this in lots of places.
11:34And recently,
11:34there were some fascinating experiments
11:36done in animals
11:38and also human surgical patients
11:40showing that what we can estimate
11:42from people's DNA
11:43about how fast they're aging
11:45suggests that aging speeds up
11:48when we get one of these traumatic stressors
11:50like a surgery
11:51and it can slow down afterwards.
11:53We also, of course,
11:54see that people who live lives
11:56characterized by higher levels
11:57of chronic stress
11:58age more rapidly,
12:00onset with disease at younger ages,
12:01and die sooner.
12:03Grant Dixon, MD, asks,
12:04You ever think about how 100 years ago
12:06doctors told people not to exercise
12:08because it would shorten
12:09their heart's lifespan
12:09and wonder what advice we,
12:11doctors, are giving now
12:12that in 100 years
12:13people will look back on
12:14and say,
12:14wow, how stupid was that?
12:16We don't have to go back 100 years.
12:17When I was a kid,
12:18we were not supposed to eat any fat.
12:20And now we know
12:21that was terrible advice.
12:22I think there are undoubtedly
12:24all kinds of medical advice
12:26that we get today
12:27that will be looked back on
12:28in the future as a bad idea.
12:30But when I think about things
12:31that have a short lifespan
12:32in terms of their received wisdom,
12:34it's going to be fad diets,
12:36particular exercise regimes,
12:38and in general,
12:38the idea that any specific program
12:41of behavior change,
12:42nutritional supplementation,
12:44or whether it's cryotherapy
12:46or cold plunges,
12:48is going to be good for everyone.
12:50What we're learning today in medicine
12:52is that every patient
12:54is their own particular medical challenge
12:56and that the optimal therapy
12:57we can deliver
12:58is going to be tailored
12:59to that person's genetics,
13:01to their microbiome,
13:02to their life history.
13:03And as we move into the future,
13:05I think medicine
13:06is going to be better
13:07at learning
13:08what makes us different
13:09from each other
13:10and tailoring therapies
13:12to each of us individually
13:13to achieve better results.
13:15A Reddit user asks,
13:16which longevity treatment
13:17will be the first to go mainstream?
13:19Well, I think, you know,
13:20healthy diet and exercise
13:21are pretty mainstream.
13:22They've been with us
13:23for an awfully long time.
13:24Caloric restriction
13:25or intermittent fasting,
13:27those are also ancient practices.
13:29And so those are
13:30sort of mainstream now.
13:31But if you think about
13:32what's new that's going to happen,
13:34I think we're going to see
13:35within the next decade
13:36medicines that are already
13:38prescribed today
13:39being repurposed
13:40as agents to slow aging.
13:43And I'm not going to take
13:44any bets on exactly
13:45which of those drugs
13:46are going to break through first,
13:47but I suspect
13:48it will be from a category
13:49that is now used
13:50to treat diabetes
13:51and metabolic dysregulation.
13:53So inflammation is a biological process
13:59and it's one that we need.
14:00So it's not all bad.
14:02There are things our body
14:03wants to get rid of
14:04and inflammation helps us do that.
14:06But too much of it
14:07can cause damage
14:08to our cells and tissues
14:09in ways that can accelerate
14:10the aging process.
14:12Inflammation can be caused by diseases.
14:14It can also be a cause of diseases,
14:15but it's definitely a mediator
14:17of the aging process.
14:19Searching for Life asks,
14:20Do those who sleep for longer intervals
14:22live longer lives?
14:23There is epidemiological evidence
14:25linking the right amount of sleep
14:28to a longer lifespan.
14:29Sleep is kind of like
14:29a Goldilocks thing.
14:30You don't sleep enough,
14:31you're going to die sooner.
14:32You sleep too much,
14:33you're also going to die sooner.
14:34But that's not necessarily
14:36cause and effect.
14:37That's just correlation
14:38when we survey people
14:39about how much they sleep
14:40and we correlate that
14:41with how long they live.
14:42And we suspect that
14:43one of the reasons, for example,
14:45shorter sleep duration
14:46may be associated
14:46with shorter lifespan
14:47is that people
14:48who are sleeping less
14:49are often engaging
14:50in other behaviors
14:51that may be health damaging,
14:53whether it's working too hard
14:55or drinking and smoking too much
14:56or living in chaotic environments.
14:59On the other hand,
15:00people who are sleeping
15:00a very long time
15:01may be doing so
15:02because they already have
15:03chronic diseases
15:04that are shortening their lifespan.
15:05That said,
15:06we do have some evidence
15:07that achieving
15:08the right kind of sleep
15:10and a decent amount of it
15:11is good for our biology
15:12in ways that could be positive
15:14for slowing the aging process
15:15and preserving healthy lifespan.
15:17Ian Yao asks,
15:17what is the impact of meditation
15:19on aging of the brain?
15:20We don't know for sure
15:22that meditation
15:23will keep us healthy for longer,
15:25but we have some
15:26very positive signs.
15:27And we think that
15:28the reason meditation
15:29has benefits for brain health
15:31and the health
15:31of the rest of our body
15:32is that it helps us manage stress.
15:35It calms us down.
15:37It allows us to connect
15:38with meaning and purpose
15:39in our lives.
15:40And even in acute treatment phases
15:43can show signs
15:44of down-regulating processes
15:45like inflammation
15:47that can damage tissues
15:48and organs.
15:48We can't tell you
15:49exactly how much meditating
15:51will slow down your aging
15:52or even what type of meditation
15:54will be most effective for you,
15:56but we do have evidence
15:57that meditative activity,
15:59finding peace in your life,
16:01can have health benefits.
16:03Bubble Brew asks,
16:04if our telomeres never shortened,
16:05could we live forever?
16:06So telomeres are
16:08repeated nucleotide sequences
16:10at the end of our chromosomes.
16:12They're actually DNA.
16:14And they act to protect
16:16the chromosome from damage.
16:18And every time the cell divides,
16:19they get a little bit shorter.
16:20We're really excited
16:21about telomeres in aging
16:23because the rate
16:24of telomere shortening
16:25functions as a kind
16:26of molecular clock
16:27for the life of a cell.
16:29But it doesn't necessarily
16:30mean the same thing
16:31if we measure it
16:32from a blood sample
16:33where we're getting telomere length
16:34in thousands of cells
16:36and across all the chromosomes
16:38in each of those cells.
16:39As for if we stop telomere erosion,
16:41would we stop aging?
16:42The answer is definitely no
16:44because we just get
16:44a lot of cancer.
16:45In fact, that's what cancer is.
16:47It's the escape from
16:48what we call
16:49replicative senescence
16:50or the way in which
16:52dividing a lot
16:53ultimately induces senescence
16:55and death in a cell.
16:56So we don't want to stop it.
16:58And as of today,
16:59there are no therapies
17:01that you can take
17:02that will elongate
17:04your telomeres in a way
17:06that will promote your health.
17:07Abundant Pecking asks,
17:09just how much of aging
17:10can actually be prevented
17:11by sunscreen?
17:12Sunscreen is definitely
17:13good for your skin
17:15and it will keep you
17:15looking younger.
17:16But I don't know
17:17that we have evidence
17:18other than protecting you
17:19from skin cancer
17:20that wearing sunscreen
17:21is particularly helpful
17:23in slowing the aging process
17:24in your internal organs.
17:26Guitar Martian asks,
17:27how will CRISPR
17:28help cure aging?
17:29There are people
17:30who have the idea
17:31that aging is caused
17:33by changes to the DNA
17:35in our cells.
17:37And CRISPR is a way
17:38to edit DNA
17:39and it could be a way
17:41to reverse those changes.
17:42But getting all the right
17:44changes made
17:44and none of the wrong ones
17:45is going to be awfully challenging.
17:47So the way that CRISPR
17:48is more likely
17:49to help cure aging
17:50is it allows us
17:51to dramatically accelerate
17:52the pace of research.
17:54We can do experiments
17:55in months
17:55that used to take years
17:57before we could edit
17:58DNA in this way.
17:59And so CRISPR
18:00is really a game changer
18:01but more in the lives
18:02of scientists
18:03than in the lives
18:04of patients.
18:05That's it.
18:05That's all the questions.
18:07Hope you learned something
18:08and until next time.
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