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0:00
I'm Dan Belsky.
0:00
I'm a professor of epidemiology at Columbia University.
0:01
I'm here to answer your questions from the internet.
0:05
This is longevity support.
0:11
SGDYNO asks, "Correlation between looking young and longevity?"
0:14
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.
0:28
There was a famous study a number of years ago by the Danish demographer Core Christensen that compared the faces of older female twins.
0:34
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.
0:45
Expedito asks, "Is it possible to halt aging and will it be in our lifetimes?"
0:51
Depends on who you ask.
0:51
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.
0:59
I tend to take a more conservative view of things.
1:01
I'm not sure we'll ever be able to stop aging.
1:04
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.
1:11
And I expect that we will see breakthroughs that can deliver at least some extension in healthy lifespan within the next decade.
1:17
Katarina Doctor Selick asks, "Tell me then, without saying anything misogynist, how do men and women age differently?"
1:24
Well, I guess the first thing I'd say is men tend to die sooner.
1:28
We have some indication that 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 may be 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.
1:50
What we do know is that men and women's bodies change in different ways as they grow older.
1:55
And if you're trying to monitor your own aging, you'll want to be comparing yourself to an appropriate reference.
2:01
One Fuzzy Blueberry asks, "Fasting and longevity?"
2:06
We've known for about a hundred years that feeding mice less makes them live longer.
2:13
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 efficiency.
2:24
So, we're not inducing malnutrition.
2:26
We're not doing starvation.
2:28
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.
2:45
And a very simple explanation of what's going on when we reduce the nutrient input into our system is we get more efficient.
2:53
Our cells start scavenging for junk, for spare parts that they can use to keep going.
2:58
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.
3:06
Floppy Plum asks, "Why don't athletes who have optimal exercise and nutrition live longer than average people?"
3:13
So, it's absolutely true that exercise is good for you.
3:15
And the healthy lifestyle that many athletes enjoy with customized diet nutrition can promote healthy longevity.
3:22
But athletes also put their bodies under intense stress.
3:26
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.
3:36
And there's some things like exercise where some of a thing can be good for you, is health enhancing.
3:42
When you lift weights, you tear your muscles and they heal back stronger than they were beforehand.
3:46
That's hormetic.
3:48
But if you put too much stress on a system, you can induce lasting damage.
3:52
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.
3:57
SCTBG asks, "Does exercise increase your longevity and if so, by how much?"
4:05
Exercise is as close a thing to a molecular fountain of youth as we have found.
4:09
It is good for literally all of us.
4:13
In terms of how much it can increase your lifespan, it's going to vary from person to person and the particular kind of exercise that's going to be most beneficial is probably different for you than it is for me.
4:22
Kaiser9798 asks, "I'm getting old. Why do all my joints hurt now? I didn't do nothing to warrant the pain."
4:28
So, the reason your joints hurt when you get old is that the tissues that cushion them shrink and and that leads to to more bone-on-bone contact to some extent and and will will cause pain.
4:40
You see an upregulation of inflammation as we grow older.
4:44
When the joints get inflamed, that will cause pain.
4:46
So, but but it is in some sense your fault in so far as it's the wear and tear we put on our bodies that causes them to age faster or slower.
4:53
And so, if you're 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.
5:00
Gehan Lacour asks, "Why do we age? Why do we grow old and die? And how does the world really work?"
5:05
I'm going to do two out of three.
5:08
We age because evolution doesn't care what happens to us after a certain point.
5:13
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.
5:20
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.
5:32
They're not maintained forever.
5:33
And that's what ultimately allows our bodies to break down as we grow older.
5:38
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.
5:53
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.
6:08
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."
6:18
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.
6:28
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 these points of acceleration around the transition to midlife, maybe 30s to 40s, and then again later in your 60s.
6:45
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.
6:57
Yogogogobop asks, "Is the whole Blue Zone thing legit? Something feels off."
7:02
Blue Zones are places that are characterized by exceptional longevity.
7:06
They're places where a lot of people get to live a very long time, maybe a hundred, maybe a hundred and five.
7:12
But to say first, the Blue Zone thing is legit in so far 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.
7:24
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.
7:40
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 live there.
7:50
And 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.
7:56
In places where those records were of lower quality or 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.
8:07
And many decades later, that can turn somebody who died at 85 into somebody who died at a hundred or even older than that.
8:15
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.
8:30
Sarira asks, "Is aging a disease?"
8:33
Oof.
8:37
This is a contentious question with big money behind it.
8:40
And the reason is that agencies like the US Food and Drug Administration that have to approve clinical trials will only let you develop drugs if they treat a disease.
8:51
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.
9:02
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.
9:10
On the other hand, aging is something we all do.
9:13
It's a normal part of life.
9:15
And others argue that as a result, we shouldn't think of it as a disease and we shouldn't try to stop it.
9:20
I think in some ways it doesn't really matter whether we call it a disease or not.
9:24
It's a process that we go through.
9:26
We like to experience it a little more slowly, maybe a little later in life.
9:30
And we think that it's reasonable to try and develop interventions to achieve that goal.
9:34
And I think we'll see that in the years ahead.
9:36
Dystopian Manor asks, "What is the potential maximum human life expectancy?"
9:40
We don't know.
9:40
There are lots of ways of asking this question, how long can a human live?
9:43
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.
9:53
They were able to collate records and compare how old uh the longest-lived person was each year uh uh until today.
9:58
So, as far as we know, the oldest person ever was woman in France, Jeanne Calment, who lived to 122 years old.
10:05
She smoked for most of her lifetime, she ate a lot of chocolate, she drank red wine.
10:08
She made it look pretty good.
10:09
Since then, the longest-lived person has always been younger than that.
10:13
And that has invited the idea that maybe this is the natural peak of human lifespan.
10:17
There are reasons to believe there is some kind of limit, but uh whether we've reached it or whether it's close to where we are today, I think we still don't know.
10:26
Kalamaja asks, "Why do people seem to age so incredibly fast after a traumatic experience?"
10:30
So, this is a great question.
10:32
Stress kills us, and it kills us in lots of different ways.
10:34
Partly because it triggers a physiological response that is designed to help us.
10:41
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 uh when our boss is yelling at us at work are not the same thing.
10:53
But evolution doesn't know that.
10:55
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.
11:09
Those processes, when chronically activated, cause wear and tear on our bodily systems in ways that make us more vulnerable to disease.
11:15
The neuroscientist Bruce McEwen called this process allostatic load, or the load that's involved in bringing our body back from that uh wild state to a kind of homeostasis or or rest state.
11:27
We see signs of this in in lots of places.
11:31
And recently, there were some fascinating experiments um done in animals and also uh human surgical patients showing that what we can estimate from from people's DNA about how fast they're aging uh suggest that aging speeds up when we get one of these traumatic stressors, like a like a surgery, and it can slow down afterwards.
11:52
We also, of course, see that that people who live lives characterized by higher levels of chronic stress age more rapidly, onset with disease at younger ages, and die sooner.
12:00
Grant Dixon, MD, asks, "You ever think about how 100 years ago doctors told people not to exercise cuz 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?'"
12:14
We don't have to go back 100 years.
12:16
When I was a kid, we were not supposed to eat any fat.
12:20
And now we know that was terrible advice.
12:21
I think there are undoubtedly all kinds of medical advice that that we get today that will be looked back on in the future as a bad idea.
12:28
But when I think about things that have a a short lifespan in terms of their received wisdom, it's going to 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 uh cold plunges um is going to be good for everyone.
12:48
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 going to be tailored to that person's genetics, to their microbiome, to their life history.
13:03
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.
13:14
A Reddit user asks, "Which longevity treatment will be the first to go mainstream?"
13:17
Well, I think, you know, healthy diet and exercise are pretty mainstream.
13:21
They've been with us for an awfully long time.
13:23
Caloric restriction or intermittent fasting, those are also ancient practices uh and so, those are sort of mainstream now.
13:31
But if you think about what's new that's going to happen, I think we're going to see within the next decade medicines that are already prescribed today being repurposed as agents to slow aging.
13:39
And I'm not going to take any bets on exactly which of those drugs are going to break through first, but I suspect it will be from a category that is now used to treat diabetes uh and and metabolic dysregulation.
13:53
Unh New asks, "Do we have evidence that inflammation drives aging?"
13:57
So, inflammation is a biological process, and it's one that we need, so it's not all bad.
14:00
Uh there are things our body wants to get rid of, and inflammation helps us do that.
14:04
But too much of it can cause damage to our cells and tissues in ways that can accelerate the aging process.
14:10
Inflammation can be caused by diseases, it can also be a cause of diseases, but it's definitely a mediator of the aging process.
14:17
Searching for life asks, "Do those who sleep for longer intervals live longer lives?"
14:23
There is epidemiological evidence linking the right amount of sleep to a longer lifespan.
14:28
Sleep is kind of like a Goldilocks thing.
14:29
You don't sleep enough, you're going to die sooner.
14:31
You sleep too much, you're also going to die sooner.
14:34
But that's not necessarily cause and effect.
14:36
That's just correlation when we survey people about how much they sleep, and we correlate that with how long they live.
14:41
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 uh or living in chaotic environments.
14:57
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.
15:04
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.
15:15
Ian Yao asks, "What is the impact of meditation on aging of the brain?"
15:19
We don't know for sure that meditation will keep us healthy for longer, but we have some very positive signs.
15:26
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.
15:34
It calms us down, it allows us to connect with meaning and purpose in our lives um and even in acute treatment phases can show signs of down-regulating processes like inflammation that can damage tissues and organs.
15:48
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, uh can have health benefits.
16:01
Bubble Brew asks, "If our telomeres never shorten, could we live forever?"
16:05
So, telomeres are repeated nucleotide sequences at the end of our chromosomes.
16:11
They're actually DNA, and they act to protect the chromosome from damage.
16:16
And every time the cell divides, they get a little bit shorter.
16:20
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.
16:28
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 uh all the chromosomes in each of those cells.
16:38
As for if we stop telomere erosion, would we stop aging, uh the answer is definitely no because we just get a lot of cancer.
16:44
Uh in fact, that's what cancer is.
16:46
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.
16:56
Uh so, we don't want to stop it, and as of today, there are no therapies that you can you can take that will elongate your telomeres in a way that will promote your health.
17:06
Abundant Pecking asks, "Just how much of aging can actually be prevented by sunscreen?"
17:12
Sunscreen is definitely good for your skin, and it will keep you looking younger.
17:16
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.
17:26
Guitar Martian asks, "How will CRISPR help cure aging?"
17:28
There are people who have the idea that aging is caused by changes to the DNA in our cells.
17:36
And CRISPR is a way to edit DNA, and it could be a way to reverse those changes.
17:42
But getting all the right changes made and none of the wrong ones is going to be awfully challenging.
17:45
So, the way that CRISPR is more likely to help cure aging is it allows us to dramatically accelerate the pace of research.
17:52
We can do experiments in months that used to take years before we could edit DNA in this way.
17:58
And so, CRISPR is really a game-changer, but more in the lives of scientists than in the lives of patients.
18:04
That's it.
18:04
That's all the questions.
18:06
Uh hope you learned something, and until next time.