

Exercise makes you healthier by purging the body of senescent cells - JumpCrisscross
http://www.economist.com/node/21543129

======
reasonattlm
Exercise boosts autophagy, yes, just like all other hormetic stressors:

[http://www.fightaging.org/archives/2011/03/an-overview-of-
th...](http://www.fightaging.org/archives/2011/03/an-overview-of-the-
molecular-mechanisms-by-which-exercise-impacts-aging.php)

It does a bunch of other things as well, many of which are likely to be as
important. The bottom line is that aging is damage - an accumulation of broken
molecular machinery in and around cells. Autophagy is a collection of repair
processes inside cells that eliminate broken machinery, allowing it to be
replaced with new-built versions. So all other things being equal you should
have a better, longer-lasting body with higher levels of autophagy, or more
efficient autophagy.

[http://www.fightaging.org/archives/2008/03/all-roads-lead-
to...](http://www.fightaging.org/archives/2008/03/all-roads-lead-to-
autophagy.php)

"Some research groups are making the case that all roads lead to autophagy,
the process of tearing down and replacing worn cellular components, when it
comes to enhancing healthy longevity through adjustments to metabolism.
Examples include calorie restriction (CR) - which you can manage all by
yourself today - or drugs that mimic some of the effects of CR on regulatory
mechanisms in our biochemistry, which you're going to have to wait a little
longer for. But it's all down to increased autophagy, they say."

(But of course all other things are never equal - that's half the fun of
trying to understand the interaction of metabolism and aging given today's
technology and knowledge. Lots of very fuzzy answers to imprecise questions).

\----

Note that autophagy runs on a bunch of machinery that can be damaged over time
just like all the rest of the cell's inner workings. The chief culprit here is
an accumulation of things that the lysosome, the furnace into which all the
broken machinery is thrown, cannot handle. So lysosomes, a roving fleet of
furnaces in your cells, become bloated and malfunctioning as you grow older,
stuffed to the gills with gunk that they can't break down.

One solution under development is bioremediation using bacterial enzymes -
supporting the SENS Foundation will help speed this research:

<http://www.sens.org/sens-research/research-themes/lysosens>

\----

Senescent cells, now, that's distantly related but a whole different thing.
See:

<http://www.sens.org/sens-research/research-themes/apoptosens>

Senescent cells have removed themselves from operation due to age or damage
and are requesting destruction - under the best of circumstances, anyway. It
is the immune system's job to kill off these lost cause cells - and the
precancerous cells, and nip a bunch of other problems in the bud while it's at
it - but the immune system becomes increasingly weak with age, and hence the
growth in the number of unculled senescence cells. These cells sit in tissue
as increasingly bad actors, well past their sell-by date, taking actions that
harm surrounding cells and structures.

Exercise impacts the immune system: it unambiguously improves it, all other
things being equal. It's not unreasonable to expect that exercise helps with
senescent cells in part because of its effect on immune system health:

[http://www.fightaging.org/archives/2011/07/aerobic-
fitness-i...](http://www.fightaging.org/archives/2011/07/aerobic-fitness-
improves-the-aging-immune-system.php)

------
westicle
This type of comment is unlikely to be popular here, but I can't help but
cringe when I read articles that disregard or make light of suffering in the
name of progress.

If I blogged about how I had started feeding my children a "diet designed to
induce diabetes" I imagine people would be appalled.

Regardless of where you ultimately fall on the issue of mistreating animals,
it is ethically lazy not to (at a minimum) turn your mind to the issue rather
than simply turning to "those stalwarts of medical research" yet again.

