
How exercise in old age prevents the immune system from declining - Luc
http://www.bbc.com/news/health-43308729
======
aacook
I've been working on a product to help families stay more connected with the
elderly people in their lives, [https://nanagram.co](https://nanagram.co). In
addition to spending a solid amount of time w/ my 94-year-old Grandpa the past
couple years the project has been a fascinating journey learning about life
after 80.

It's so awesome to see an 82 year old guy on his road bike in the video on
this article!

Susan Pinker has a fascinating Ted talk on the secret to a long life. For
years I'd always assumed things like diet and exercise would be the top
factors. But according to Pinker social integration is the top factor, even
higher than drinking and smoking (which, somehow, are higher than exercise).

[https://www.ted.com/talks/susan_pinker_the_secret_to_living_...](https://www.ted.com/talks/susan_pinker_the_secret_to_living_longer_may_be_your_social_life)

This study is about endurance cyclists, showing them riding in social groups.
Is exercise really the top factor here? Or is it riding in social groups?
Maybe it's a combination of both.

I've seen the impact regular exercise can have on my own physical and mental
health and on my Grandpa's. Past age 90, exercise can become a real challenge.
At this stage, my Grandpa has a couple in-home nurses who visit and help him
complete various exercises each week, lifting his arms above his head, moving
his legs, etc. Other than that, I try and visit him as often as possible. We
do simple things, like shop for groceries together, to keep him moving.

One of the most eye opening experiences for me on old age was about 18 months
ago just after my Grandpa stopped driving at age 93. I started visiting him
more and we began a genealogy project of sorts. At first his memory wasn't so
great. But after a month or so of regular visits, it was like a fire was
ignited. All of the sudden he was reciting incredible facts and figures about
the past. He kept up with all the little details in my life better than many
of the people I know in my 30s. And there was a new pep in his step. It's rare
to live past 90. I'm grateful for every day I get with my grandparents, both
94 and under 30min from me. If you have an older person in your life, I
encourage making as much time as possible to visit. There's so much you can
learn from them and your visits can have a positive impact on their life too.

------
DoreenMichele
A different study found that intense exercise reverses aging at the cellular
level: [http://www.health.com/fitness/anti-aging-hiit-
workout](http://www.health.com/fitness/anti-aging-hiit-workout)

The body process lymph several times more efficiently while active. This is
how the body removes wastes from tissues. Seems to me that would be pertinent.

------
reasonattlm
Given that this study focuses on declining naive T cell production and thymic
tissue loss, it is interesting to look at another recent study that suggests
these losses are the dominant cause of increased cancer rates with age.

[https://doi.org/10.1073/pnas.1714478115](https://doi.org/10.1073/pnas.1714478115)

T cells develop from hematopoietic stem cells as part of the lymphoid lineage
and have the ability to detect foreign antigens and neoantigens arising from
cancer cells. In the thymus, lymphoid progenitors commit to a specific T cell
receptor and undergo selection events that screen against self-reactivity.
Cells that pass these selection gates then leave the thymus, clonally
expanding to form the patrolling naive T cell pool.

The vast majority of vertebrates experience thymic involution (or atrophy) in
which thymic epithelial tissue is replaced with adipose tissue, resulting in
decreasing T cell export from the thymus. In humans, this is thought to begin
as early as 1 year of age. The rate of thymic T cell production is estimated
to decline exponentially over time with a half-life of ∼15.7 years. Declining
production of new naive T cells is thought to be a significant component of
immunosenescence, the age-related decline in immune system function. With the
recent successes of T cell-based immunotherapies, it is timely to assess how
thymic involution may affect cancer and infectious disease incidence.

It is clear from epidemiological data that incidence of infectious disease and
cancer increases dramatically with age, and, specifically, that many cancer
incidence curves follow an apparent power law. The simplest model to account
for this assumes that cancer initiation is the result of a gradual
accumulation of rare "driver" mutations in one single cell. Furthermore, the
fitting of this power law model (PLM) can be used to estimate the number of
such mutations. Exponential curves have also been used to fit cancer incidence
data, resulting in worse fits than the PLM overall. Nevertheless, it is worth
noting that exponential rates close to the declining curve for thymic T cell
production can be seen to emerge from the incidence data, indicating the
relevance of the thymic involution timescale. While the PLM fits well, it does
not account for changes in the immune system with age. To better determine the
processes underlying carcinogenesis, we asked whether an alternative model,
based only on age-related changes in immune system function, might partly or
entirely explain cancer incidence.

Our model outperforms the power law model with the same number of fitting
parameters in describing cancer incidence data across a wide spectrum of
different cancers, and provides excellent fits to infectious disease data. Our
hypothesis and results add to the understanding of infectious disease and
cancer incidence, suggesting in the latter case that immunosenescence, rather
than gradual accumulation of mutations, serves as the predominant reason for
an increase in cancer incidence with age for many cancers. For future
therapies, including preventative therapies, strengthening the functionality
of the aging immune system appears to be more feasible than limiting genetic
mutations, which raises hope for effective new treatments.

~~~
nonbel
>" _Given that this study focuses on declining naive T cell production and
thymic tissue loss, it is interesting to look at another recent study that
suggests these losses are the dominant cause of increased cancer rates with
age.

[...]

Our model outperforms the power law model_"

Interesting, since cancer "rates" (age-specific incidence) for many cancers
peak at 60-90 years old. This paper looks like they cut off the data at 85
years, ignore the peaks during youth, and aggregate the data in such a way (eg
colon and rectum grouped together) to force a power law fit.

EDIT:

Also, they just say "data from SEER". What years did they use, inclusion
criteria, etc?

------
said
I have a concern.

A few months ago, a widely publicized study[1] indicated that moderate-to-
large amounts of exercise caused a buildup of plaque in the hearts of middle-
aged white men. This correlation was not seen in any women, nor was it seen in
black men.

Unfortunately, this study included no Indian nor Southeast Asian people. I've
seen unrelated studies indicating similar health outcomes for white men and
Indian men, so as an Indian man, should I be worried about this?

[1]: [https://today.uic.edu/physically-active-white-men-at-high-
ri...](https://today.uic.edu/physically-active-white-men-at-high-risk-for-
plaque-buildup-in-arteries)

~~~
hypersoar
Not even middle-aged white men should worry about it. It was more "This
population had the highest coronary artery calcification, which matches what
other studies have found. We should look into it more" rather than "These
white dudes gotta slow down or their hearts'll give out".

~~~
said
I appreciate your response. I’m under the impression that the white men who
exercised more had more calcification:

> Instead, Laddu and her colleagues found that participants in trajectory
> group three, or those who exercised the most, were 27 percent more likely
> than those in trajectory group one to develop CAC by middle age. CAC was
> measured during the participants’ 25th year in the study using computed
> tomography, a CT scan, of the chest. At year 25, participants were ages 43
> to 55.

------
rubicon33
If you work at a desk all day and are interested in being more active, take a
look at Desk Cycle:

[https://deskcycle.com/](https://deskcycle.com/)

I got one a few months ago after reading a testimonial in a similar thread
here on hacker news. Mine sits permanently under my desk. I have nothing but
positive comments to say about it. Fit's nicely under the desk, works
wonderfully.

~~~
byproxy
Looks good for perpetual foot-tappers, too.

Would be good if it could generate power...maybe charge up a device a bit in
the process.

------
stangles1
I'd be curious to know if similar effects are observed in orthogonal types of
physical activity from cycling, e.g. strength training.

~~~
juanmirocks
I hear often that strength training is more beneficial as, supposedly,
increments your growth hormone levels.

I'm also interested in a listing of publications comparing different physical
activities for their fitness related to improving health overall and anti-
aging concretely. ?

------
Luc
The publication this is based on is open access:
[http://onlinelibrary.wiley.com/doi/10.1111/acel.12750/full](http://onlinelibrary.wiley.com/doi/10.1111/acel.12750/full)

------
known
Metformin acts on a number of hormone receptors which are also affected by
Calorie Restriction for long and cancer free life
[https://www.economist.com/news/briefing/21704788-fight-
cheat...](https://www.economist.com/news/briefing/21704788-fight-cheat-death-
hotting-up-adding-ages)

------
Retric
I don't think it's any one thing. Exercise helps people stay connected with
others. Being healthy enough for exercise is important, but regular exercise
also makes illness more obvious. If you stay at home watching TV then feeling
bad does not change much, if you normally bike around then dizzy spells become
really noticeable.

------
scottrogers
On a 5 hr bike ride your body is going to go into a similar state as
intermittent fasting with all your glycogen being burned off. Similar to
fasting this frees up energy and allows the garbage in your system to be
burned off.

~~~
michaelcampbell
I do a ~24 hour fast weekly, and a LOT of sites go into this "burning off
garbage" or "toxin cleaning" rhetoric which always puts me in "bullshit
warning" mode. Is there actual science behind these claims?

~~~
hazeii
The 'detox' side of it is very likely garbage (but a great way to sell); on
the other hand, 5-hour bike rides without fuel will deplete your glycogen
stores and there'll come a point where the differnce becomes obvious (see
'bonk-training').

A 24-hour fast is different; your body will burn fat at sufficient rate to
avoid glycogen depletion (it's pretty simple; the harder you exercise the less
energy comes from fat and more from 'carbs').

From a weight-less perspective though all that matters is calories out exceed
calories in - it's quite possible though that fasts end up making you less
hungry than hard exercise does.

Long-distance cyclists don't worry about any of this though - the approach is
actually pretty simple:-

Press food to face.

Suck.

Repeat.

Edit: formatting.

~~~
fpoling
In one of his articles Ray Cronise gave some numbers that even with light
jogging or even fast walking for fuel body uses carbohydrates exclusively. So
cardio exercises are a bad way to loose weight. They made people hungry. And
as people eat all the fat from the food is stored as body fat and may not be
burned until the next exercise.

~~~
hazeii
That's pretty much it; although at higher intensities the calories per unit
time is higher, the higher the intensity the more comes from short-term stores
(glycogen) than from long-term (fat).

The numbers suggest 60 to 70 per cent of max heartrate (which is pretty easy)
is the sweet spot for general fitness and fat burning (i.e. weight loss). For
improved endurance, spend a lot of time in that zone; for improved performance
spend shorter periods (well) above it.

------
Agebor
\- is it correlation or causation? \- could the causation be in the other
direction?

You always need to ask these questions. Perhaps senior people who have immune
systems as 20-year olds, are much more likely to cycle in old age. Or there is
some other reason that causes both.

~~~
wukerplank
Does it matter that much? Just be active for as long as possible and reap the
benefits of fit muscles and a stronger heart.

Purely anecdotal: My grandfather is nearing 90 and still jumps on his indoor
bike every day. Last winter he fell (due to ice) and got away with a few
bruises. For other people his age this kind of fall could have meant a broken
hip. He had two heart attacks when he was around 60 and a life long lung
disease - far away from the immune system (or health) of a 20-year old.

~~~
nmeofthestate
Of course it matters. If the old cyclists are just genetically superior, then
prescribing 100 mile bike rides to frail old people might be damaging, rather
than transforming them into disease-resistant superhumans.

~~~
wukerplank
Why would you prescribe a 100 mile ride to an old person?

My point was that living a long and fairly healthy life is a day to day
project, not a pill you take once you hit 70.

------
spodek
Saying exercise prevents decline normalizes being sedentary.

I prefer considering exercise normal and saying its lack accelerates decline.

Anyone is free to call normal what they want, but I find my way leads me to
live more healthy.

~~~
matwood
This is a great way to put it. I've been exercising so long that it is my
normal. Not exercising for more than two days in a row and I start to feel
weird/not healthy. This has led me to end up on the treadmill at 10pm or 5am.
When it becomes your normal it is just like breathing or eating.

~~~
devgutt
Same to me, but I was more active when I was living in a warm country. Now I
am living in a mildly cold winter country, and struggling to go out out to
walk/run because of the cold. 3 weeks and I already feeling less productive
and healthy.

~~~
tacoman
Running in the cold is great. I run outside until it gets below -20 deg C.
Some thermal tights and a few layers on top is all you need. It took me quite
a few years to finally just give it a try and now I actually prefer running in
the winter vs summer.

~~~
Moru
There are masks you can wear that makes it easier to breath the cold air for
running when it's even colder. I guess it heats the air a bit. I like walking
in the cold, just have to dress for it and not overdo it so you overheat in
your nice warm clothes :-)

I haven't tried the breathing masks though I probably should since I have
asthma and breathing in the cold makes it worse.

~~~
CompelTechnic
Are they the sort of mask that makes you look like subzero from Mortal Kombat?
I've been thinking about getting one.

~~~
Moru
I dont know about those, the one I saw looked like an asthma inhalator I
think. But this was long ago.

------
reasonattlm
Publicity materials: [https://theconversation.com/exercise-can-slow-the-
ageing-pro...](https://theconversation.com/exercise-can-slow-the-ageing-
process-a-professor-explains-how-93020)

Paper:
[https://doi.org/10.1111/acel.12750](https://doi.org/10.1111/acel.12750)

This age of biotechnology is also an age of comparative indolence and comfort.
As the research community measures specific biochemical aspects of aging, such
as the decline of the cardiovascular system, or metrics relating to
immunosenescence in the immune system, we might question the degree to which
the results are peculiar to our era. How much of aging is the result of our
choices - to eat more and exercise less than our ancestors - rather than the
result of inexorable processes of biochemical damage that we, as yet, have
little influence over? (Conversely, how much of past aging was due to
infectious disease, malnutrition, and other adverse external circumstances
that are controlled to a much greater degree today?) This topic crops up
fairly often in research into the effects of exercise on health, and the
research noted here is a particularly striking example of the type.

The study authors find that the age-related decline of new T cells maturing in
the thymus is negligible in some people, those who exercise much more than the
rest of us. This diminished supply of new T cells is thought to be an
important component of immune system aging, and the failure of the immune
system is very influential over many other aspects of aging: senescent cell
accumulation, frailty, loss of regenerative capacity, chronic inflammation,
cancer risk, and so on. Yet when we look at the demographic evidence for
spread of life span based on exercise, it appears to be, at most, 6 or 7 years
(with a much larger divergence when it comes to state of health over time).
What does this tell us about the likely gains resulting from rejuvenation
therapies seeking to regenerate the thymus? Less than we would like, I
suspect, and not just because it is hard to evaluate any one contribution to
aging in isolation of all of the others.

The thymus atrophies over adult life, with active tissue necessary for the
production of T cells being replaced by fat. The first major loss of active
thymic tissue occurs at the end of childhood, however, in a process known as
involution. Immune cells are generated at a tremendous rate in children in
comparison to young adults; evolution selected for a system that would be
highly effective at the outset, at the cost of later issues. When it is
observed that old people in their 60s and 70s who maintained a high level of
fitness throughout life exhibit much the same thymic output as young people in
their 20s, that tells us little regarding the outcome were the thymus restored
to the same level of active tissue as is present in children. Only a mild
restoration, to move thymic activity from typical aged to typical young adult,
would be comparable - and why would we stop there?

