
Telomere shortening rate predicts species life span - bookofjoe
https://www.pnas.org/content/early/2019/07/02/1902452116
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jes5199
this makes me think that telomeres are not the main cause of aging-related
death. My mental model is: if you run out of telomere before you get old, you
start to get disease - and that’s maladaptive. So there’s evolutionary
pressure to slow down your shortening rate, up to a point. Once it becomes
unlikely that you’ll outlive your telomeres, there’s no more pressure. So your
telomere length + rate becomes a _measurement_ of your species lifespan.

~~~
jayd16
This doesn't really make sense does it? There's only really evolutionary
pressure up to the end of your child rearing years, no?

~~~
anticensor
Humans are double-viviparous species, meaning average grandparent lives past
its grandchild's puberty. Humans are also atricial. These traits are shared by
elephants, whales and dolphins too. However, humans are the only animal
species those are triple-viviparous in occasions, meaning great-grandparent
lives past its great-grandchild's puberty.

~~~
collyw
Human's average lifespans have been a lot shorter throughout history.

~~~
tomp
Average isn't that relevant. It's driven down by early childhood deaths &
childbirth deaths (but after a point - menopause - childbirth deaths end).

~~~
collyw
Infectious disease killed many before old age. Antibiotics are a pretty recent
invention.

~~~
tomp
Yeah, but the impact isn't _that_ great.

According to _Our World In Data_ [1] a 20-year-old would expect to live to 60
in 1850 (before penicillin), versus to 80 now.

[1] [https://ourworldindata.org/life-expectancy#it-is-not-only-
ab...](https://ourworldindata.org/life-expectancy#it-is-not-only-about-child-
mortality-life-expectancy-by-age)

~~~
Tade0
That's still long enough for a person to see their grandchildren reach and
cross puberty.

~~~
isostatic
Especially in a world where kids were born when the parent was in late teens
or early 20s, rather than now when average age is 28 and pushing higher.

This means first grandchildren in early 40s (rather than late 50s), and first
great grandchildren by mid 60s (rather than mid 80s)

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i000
One of the biggest challenges for studying telomere biology in the context of
human aging, is that mice are quite different from humans in terms of their
telomere structure.

The shortes mouse telomere is longer than the longest human one

[https://www.ncbi.nlm.nih.gov/pubmed/23956466](https://www.ncbi.nlm.nih.gov/pubmed/23956466)

~~~
no_identd
Sure, but we have way more research on this already, from humans:

[http://doi.wiley.com/10.1002/jez.b.20006](http://doi.wiley.com/10.1002/jez.b.20006)
Stindl, Reinhard - Is telomere erosion a mechanism of species extinction?
(2004)

[http://link.springer.com/10.1007/s00114-014-1152-8](http://link.springer.com/10.1007/s00114-014-1152-8)
Stindl, Reinhard - The telomeric sync model of speciation: species-wide
telomere erosion triggers cycles of transposon-mediated genomic
rearrangements, which underlie the saltatory appearance of nonadaptive
characters (2014)

[http://molecularcytogenetics.biomedcentral.com/articles/10.1...](http://molecularcytogenetics.biomedcentral.com/articles/10.1186/s13039-016-0224-1)
Stindl, Reinhard - The paradox of longer sperm telomeres in older men’s
testes: a birth-cohort effect caused by transgenerational telomere erosion in
the female germline (2016)

more here:
[http://telomere.at/publications.html](http://telomere.at/publications.html)

also some old-as-fuck news coverage (2004):
[https://www.theguardian.com/education/2004/apr/08/science.hi...](https://www.theguardian.com/education/2004/apr/08/science.highereducation)

[https://www.newscientist.com/article/mg18224421.400-chromoso...](https://www.newscientist.com/article/mg18224421.400-chromosome-
clock-ticks-out-our-fate/)

oh and, a letter where Stindl outlines the problem in detail:
[https://www.researchgate.net/profile/Reinhard_Stindl/publica...](https://www.researchgate.net/profile/Reinhard_Stindl/publication/280049041_The_reanalysis_of_three_large_datasets_uncovers_progressive_telomere_erosion_between_healthy_human_generations_and_supports_an_11-year-
old_model_of_telomere-
driven_macroevolution/links/55a5467808ae81aec9134810.pdf) Stindl, Reinhard -
The reanalysis of three large datasets uncovers progressive telomere erosion
between healthy human generations and supports an 11-year-old model of
telomere-driven macroevolution (2015)

I find it EXTREMELY strange that the OP paper cites NONE of these papers.
Like, what the hell?

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fny
Hasn't this been known for a while now? I swear I learned about this in AP Bio
a decade ago.

~~~
QuickToBan
You probably learned about the telomere length, not the shortening rate.

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PhilWright
The total number of heartbeats also predicts lifespan, although apparently not
as accurately. So is the heartbeat total just a coincident or still a factor
somehow?

~~~
axaxs
I've seen this before and get the gist, but at face value, it's ridiculous. A
human who runs every day may expend twice the heartbeats of a sedentary
person. He or she will not live half as long, or anything close to it.

~~~
function_seven
I think the idea is that a frequent runner will have a much lower resting
pulse rate, and the “extra” beats they use while exercising will be more than
offset by the fewer beats that accumulate during rest?

I haven’t done the math though.

~~~
copperx
That's the assumption, but I have never seen or done the math either, which is
ridiculous because it shouldn't take more than 5 minutes to get some
estimates.

~~~
function_seven
Okay, you shamed me into doing it :)

So, this is really rough napkin math, but here goes:

Assuming that...

... a sedentary person (Donald) has a resting BPM of 80.

... an active runner (Justin) has a resting BPM of 60, and a peak BPM of 180
(while running)

If Justin runs for a solid 2 hours, five times a week, he will have

    
    
        158*60*60 + 10*60*180 = 676,800 beats per week
    

While Donald, who doesn't run, but averages 1 hour a week doing strenuous
activity, will have

    
    
        167*60*80 + 1*60*180 = 812,400 beats per week 
    

Donald's heart beats 20% more often than Justin's. (And that's assuming
Donald's heart also peaks at 180.)

 _(Edited to change names and fix math errors)_

~~~
mrfusion
Thanks for doing the math. I’d say 130-140 would be better than 180 for
someone in shape.

Most people can’t even hit 180 after their 20s.

~~~
copperx
No wonder I dread going to the gym, I find it really strenuous. I'm 37, unfit,
and try to hit 180 while running on a treadmill. I was using the same target
BPM that I used in college.

Thanks! I'll try 160 BPM next time. Running 45 mins should be more doable.

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mdani
For humans, about 15 kbp telomere can be reduced to 50% in about 107 years at
the rate of about 70 bp per year. That number goes well with the max life
spans we observe in humans.

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peter_retief
The life span of a species can mean at least two things. The lifespan of
individuals that belong to the species or how long the entire species can
survive without mutating. I believe extinction, species lifespan and the
theory of recapitulation (ontogeny recapitulates phylogeny) are intertwined
[https://en.wikipedia.org/wiki/Recapitulation_theory](https://en.wikipedia.org/wiki/Recapitulation_theory)

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alok-g
I had read somewhere that telomere length reduces each time a cell divides.
Assuming that, telomere shortening rate is directly indicative of the number
of times cells have gone through division. Could that not mean that telomere
shortening rate is just estimating cell division rates and the latter relate
to life span for an entirely different reason? Is this or some other study
show that shortening rate is a better predictor of life span than cell
division rate?

~~~
bufferoverflow
Telomeres eventually end, and that's the difference.

~~~
alok-g
It would help if you can explain more.

If telomere's ending were of significance, then their lengths would be a good
predictor of life span. The OP is saying that it's not the length but the
shorting rate that counts.

~~~
bufferoverflow
The length too. We've known that for a while. The rate is this new discovery
(though not really, we've known it since 2018).

2017:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5425118/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5425118/)

2012:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277142/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277142/)

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Rch_East
How do we slow our personal telomere shortening rate?

~~~
keenmaster
Other than being born with the right genes? Moderate exercise, like 30 min. of
cardio 3 times a week, may help increase telomere length just as much as
marathon running. Omega 3 and most things associated with a good diet also
correlate with longer telomeres. A study showed that processed meat (like
bologna with nitrate) has a negative effect on telomeres. Go figure.

There is a very strong negative association between chronic stress and
telomeres. The worse the stress is and the longer the episode, the more your
telomeres are impaired. If a woman is chronically stressed or had low
emotional support in childhood, her kids may get shorter telomeres in utero.
Social isolation also seems to be terrible for telomere length.

Disclaimer: Telomeres are a relatively new area of interest. Studies showing
the above haven’t been replicated enough to be comfortably stated as fact. Of
course, telling correlation from causation is difficult.

~~~
curious_one
You can actually increase your telomeres? Is there a way to get them measured
accurately?

~~~
keenmaster
Yes there are several companies that do this. TeloYears is one. They use a
blood sample to index your telomere length (actual length) against other
people your age (expected length). One of the outputs is a percentile rank for
cellular age. While this can be useful information, there are a couple issues.
One is that you can’t reliably predict expected lifespan simply using telomere
length. The other is that it is over $100. You already know if you’re healthy
and have good genes. I guess it could be used for benchmarking to see whether
your telomeres are on the right track.

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JohnJamesRambo
Teloyears.com. I got my telomere length measured and found it quite
interesting and useful.

