
Fatigue Is a Brain-Derived Emotion that Regulates to Ensure Protection (2012) - cpncrunch
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3323922/
======
mrexroad
My first thought was, "oh, reminds me of the SEAL's 40% rule... so if they're
trained to ignore that limit, why don't they get hurt?" Then, in first google
result [1], I read this:

“I first met “SEAL” at a 100-mile run in San Diego and I was running this race
as part of a six-person relay team with friends and he was running the entire
race by himself,” Itzler said.

“Who is this guy? I’ve never seen anything like it. And during the race, I
kept an eye on him and around mile 70 — he weighed probably 260 pounds, which
is quite large for an ultra runner — he had broken all the small bones in both
of his feet and had kidney damage and he finished the race.”

So... yeah, this makes Me think maybe I'll try harder at listening to my body
(fwiw, I've screwed up arms/hands twice in past decade by pushing through
fatigue).

[1] [http://thehustle.co/40-percent-rule-navy-seal-secret-
mental-...](http://thehustle.co/40-percent-rule-navy-seal-secret-mental-
toughness)

~~~
ArkyBeagle
Where does this come from in the larger culture? I can see why people who are
soldiers or ... athletes at the varsity or pro level might be interested in it
but why would anyone want to basically injure themselves as a ... hobby?

I've worked with runners who had serious injury, soccer players who came in
with bruises that you'd associate with a severe beating... I'm thinking "geez,
it's gonna suck when you're 62." Because when you lose some amount of basic
mobility, you lose a lot of the ability to stay healthy when you're older.

Is this because of Mountain Dew commercials and 1980s GI Joe body image stuff?

~~~
lj3
> soccer players who came in with bruises that you'd associate with a severe
> beating

I was a lacrosse goalie in high school and didn't have the sense to wear shin
pads. If you run your fingers along my shin, you'll feel divots where the bone
never regenerated. I too used to walk around with bruises on my legs that
you'd associate with a severe beating.

> Is this because of Mountain Dew commercials and 1980s GI Joe body image
> stuff?

It's considerably more primal than that. Sports are the modern equivalent to
tribal rites of passage. We're not allowed to kill our rivals anymore, so we
settle for beating them in a physical sport in order to establish our physical
dominance. It's empowering in a way that few things are, especially as a
teenager and extra especially if you were bullied throughout elementary
school.

~~~
ArkyBeagle
I was 120 lbs soaking wet when I was 17. The school gently guided me away from
sports. Good thing, too. Best coach I ever had.

I graduated high school close to 1980. Sure, there were guys finishing the big
game on a broken bone but it seems like there's a lot more emphasis on this
now, and it seems more dangerous and higher risk. I have nephews and kids of
friends who are electing out of organized sports.

FWIW, I feel lucky - we had basically _one_ bully and he didn't last.
Expelled.

I remember in "Brian's Song" where Alex Karrass' character sold cars in the
pro football off season.

I dunno; I saw "Bigger, Stronger, Faster" and it gave me pause.

~~~
lj3
When I was 16, I was 130. That's after I spent three years in the weight room
every day putting on muscle. I played every sport my school offered at least
once, but I played football for 8 years. I never regretted it and I encourage
everyone, especially the indoor geeky types, to try out for sports. Any sport.
Even historical sword fighting. ;) It's an important experience that fewer
kids are getting exposed to in this day and age thanks to helicopter
parenting. Not to mention the life long social and health benefits

~~~
saiya-jin
there are sports which will cripple your health in long run, almost
guaranteed. many contact sports, it football comes to mind. some of my high
school classmates are semi-cripples because of it (they can walk around, and
that's about it). depression can be seen in their eyes - once you know what
having a healthy and strong body means, and then losing it forever.

I've done my share of team/contact sports in my youth. nothing horrible
happened apart from few broken fingers, but stuff I do now makes those sports
look super boring/borderline idiotic when looking back (ie coach yelling at
you like a little girl, running you around 'to break you to unlock your
potential'). What I mean - trekking, skiing, climbing, via ferratas, cycling
on unpaved roads, a bit of easy ski alpinism and mountaineering.

but I agree that any activity/sport is endlessly better than none, that's for
sure

~~~
wallflower
> depression can be seen in their eyes - once you know what having a healthy
> and strong body means, and then losing it forever.

I've talked to a friend of a friend who basically doesn't fear what normal
people fear (e.g. talking to beautiful women, surfing, rock climbing, talking
to strangers - he is really successful at sales). I asked him what his biggest
fear was. He said it was to his lose health/lose control of his body (e.g. bad
accident/paralysis).

We all have fears, and I think, in the end, we all fear mortality. And those
who don't have the fears we most have (e.g. talking to beautiful women), fear
their mortality/fragility of even the most fit body the most.

~~~
ObeyTheGuts
I never get whats the difference talking to beautiful women compared to anyone
else? Im reserved and dont talk people much but there is no difference at all
who those people are! Overall talking women is even bit easier as they are
less dangerous on average.

~~~
orbitur
For me, it's probably a holdover from my teenage years as a socially awkward
and horny boy. I'm in my 30s now, but there's weird mental habits and impulses
that are still sticking around.

I'm happily married, I don't cheat, I don't want to cheat, I'm really not
interested in the "hot woman," but if I end up talking to her under any
circumstances, there's a loud chorus of voices in my head screaming
"dontfuckitupdontfuckitupdontfuckitup." I push through and get over my initial
nerves, because I'm a grown up, but it's awful and annoying and I wish it
would go away.

~~~
ObeyTheGuts
Wow, interesting stuff, i cant imagine any situation like that, even if i was
operating my kid in life or death surgery i would not have dontfuckitup in my
head, am i psychopath?

------
gwern
'Protection' might be the goal of physical fatigue, but it doesn't work for
intellectual effort - what are you being 'protected from breaking' by not
being able to write another line of code? Carpal tunnel? In that case, it
looks more like it's about conserving energy or rotating to another task after
having spent so much time on one task: "A Meta-Analysis of Blood Glucose
Effects on Human Decision Making"
[http://www.gwern.net/docs/2016-orquin.pdf](http://www.gwern.net/docs/2016-orquin.pdf)
, Orquin & Kurzban 2016 "An opportunity cost model of subjective effort and
task performance"
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856320/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856320/)
, Kurzban et al 2013

~~~
halayli
What about mental fatigue? The more you workout your brain the more it needs
to rest. How would you like your brain to tell you that it needs to rest other
than feeling fatigue?

I find myself consistently productive over long spans without a burnout effect
when I am sleeping at consistent hours, and working for consistent hours a
day. When I overwork my productivity becomes inconsistent so I stopped doing
that. I learnt it the hard way that late night coding is a short-term
investment with negative return in the long run.

My personal theory is that our brains like consistency and adapt/tune to it
over time. Just like when you jog every day, if you run for too long one day
and too short the other day it cannot adapt/tune itself to a semi-random
pattern.

~~~
mamon
I heard different story: there is no such thing as "mental fatigue". The
reason why we get tired when doing office work is:

\- our muscles need to support our body while sitting. \- most mental work
includes some dose of stress, which is a real reason of fatigue.

Buy yourself best chair you can find plus do stress-free, enjoyable work and
you can go 16 hours straight, without fatigue. At least that's how I felt
about all-weekend-long Quake matches back then when I was living in dormitory.

~~~
cpncrunch
I think it depends on the task. Playing Quake doesn't require significant
amounts of creativity or learning, in the same way that programming or
learning a new language would. We know that the brain needs sleep in order to
process new memories, so that may be one factor in mental fatigue.

------
taneq
This meshes perfectly with the general view of endurance athletes that
performance is largely mental. If fatigue was strictly limited by lactic acid
buildup then your state of mind wouldn't make such a dramatic impact.

~~~
wallflower
> This meshes perfectly with the general view of endurance athletes that
> performance is largely mental.

Most elite endurance athletes do not hit the lactic threshold during their
actual races. That is why they train so much - to build their endurance. Once
you hit the lactic threshold, your body starts to break down.

~~~
mantas
Enduramce athletes go just bellow lactic threshold most of the time. The body
is OK to go above threshold, but only for a limited time. The key is to
correctly time usage of that above-threshold capability.

I race MTB. Both quick races and long, 100 miles or even 24h solo events. In a
quick <3h race, I just go all-out and stay above threshold most of the time.
But I try to time my above-threshold usage in long races. In one of the 24h
races, the course had a single climb. I was riding everything but that climb
bellow threshold. It would have been very hard to stay bellow threshold on it.
While it was just a couple minutes effort above threshold.

------
deciplex
Anyone who has gone to the gym after a protracted absence and loss of fitness
will have some intuitive understanding of this. Your brain hasn't quite gotten
the memo that you're not in the shape you used to be, and it's really easy to
over-exert yourself. You feel fine during the workout, then throw up afterward
and take much longer to recover.

~~~
cpard
Very true. I learned this the hard way, in my case I ended up with a stress
fracture. My mind was actually refusing to get the memo, even when I started
feeling pain.

------
js2
Dr. Noakes, the author of this paper, wrote the "Lore of Running", which may
be descibed as the bible on running science:

[http://www.humankinetics.com/products/all-products/lore-
of-r...](http://www.humankinetics.com/products/all-products/lore-of-
running-4th-edition)

[https://en.m.wikipedia.org/wiki/Tim_Noakes](https://en.m.wikipedia.org/wiki/Tim_Noakes)

------
yuningalexliu
In light of this article, wonder what type of psychological training could be
used to complement the typical physical training to improve athletic
performance?

~~~
gryphonshafer
Maybe something that copies military basic training. It has been decades, but
I can still hear my drill instructor yelling, "You aren't tired until I tell
you you're tired!" He was right.

~~~
sangnoir
> I can still hear my drill instructor yelling, "You aren't tired until I tell
> you you're tired!" He was right.

I wonder why Rhabdo[1] isn't more prevalent in basic than it is.

1\.
[https://en.wikipedia.org/wiki/Rhabdomyolysis](https://en.wikipedia.org/wiki/Rhabdomyolysis)

~~~
gryphonshafer
>90% of fatigue in basic (based on a scientific study I just made up in my
head) is mentally induced because recruits have a belief of their limits
that's short of reality. Part of the drill instructor's responsibility is to
demonstrate these limits are just mental by pushing recruits beyond them. Of
course, that still leaves the <10% of times when the limits are real and
someone gets hurt, but that's just collateral damage, I guess.

~~~
projektir
I wonder if it's really 10%. The instructor most likely doesn't actually know
the person's limits. They're setting a baseline and hoping everyone has good
enough genetics to meet that baseline. The rest are injured/kicked out/may
have actually been filtered out earlier. Remember that the military turns down
many people, and that often includes a lot of people who have hidden medical
issues or just bad genetics.

------
nnq
This also makes sense if you think the evolutionary biology of it: if after a
small number of top runners separate from the pack (even if they happen to be
the "top" runners of a race by pure luck, and even if their relative order is
pure luck), it's better if the 2nd, 3rd runner etc. accept their places at a
point and don't push more, because then the top runner will also push more and
so on... positive feedback loop until some of them (maybe all!) _die_ of
fatigue.

 _Cowardice of the individual might be a huge survival advantage for the
species as a whole!_

Without it the species might end up loosing or injuring the fittest of the
individuals in stupid competitions. The would be quite detrimental for the
species.

(Also going even further from physical performance: If you extend this a bit
from "athletic race" to "nuclear arms race" you'd see a similar thing ...but
yeah, as an individual player you might "loose" by being coward (although I
would not call "staying alive" loosing...).

And an interesting philosophical question would be about the cases where an
individual _gains courage by loosing "the feeling of being the same species as
the others"_ \- we know that psychopaths ca be quite fearless, and we also
know from history that if you train your soldiers to think they are "a
superior master race separate from the others" they tend to get quite better
at winning battles.)

------
towlejunior
If the claim is that muscles don't fatigue, then I am skeptical.

In college, I took a weightlifting class with a bunch of athletes in it. One
day, we did lunges (no weight) around and around, in a line like ants. Nearing
the end, my brain thought I was totally fine. I cannot stress that enough.
Bam, like a light switch, my legs went from 60% strength to 2% three quarters
of the way through the last lap. Had the instructor not caught me, I would
have fallen right over.

~~~
fernly
No, I think you are anecdotally supporting the posted article: you worked your
muscles to physical exhaustion but you did not feel "fatigue", ergo, the
conventional theory that "fatigue" is caused by lactic acid or other muscle
chemistry is disproved.

~~~
jcoffland
What result would disprove the article?

------
bootload
_" conscious mental decisions made by winners and losers, in both training and
competition, are the ultimate determinants of both fatigue and athletic
performance."_

A favoutite quote of mine: _" You have to make a sustained 'conscious effort',
to win."_

------
ilaksh
I can buy the conclusion except that I believe you can only usually tweak
performance in small degrees without actually over-exerting yourself, since
the central nervous system _is_ in fact an expert on what you are capable of
doing safely.

~~~
cpncrunch
I think the point is that you can _keep_ increasing performance in small
degrees, so it's kind of like training your brain to allow small incremental
performance boosts by saying "see, I didn't get injured or die, so give me
another 1% speed". Of course, sometimes this does actually result in injury,
so if you want to be safe it's probably best not pushing too far.

------
liquidise
"Fatigue makes cowards of us all" is a famous quote supposedly from Vince
Lombardi, though it has also attributed to other significant people (as famous
quotes often are).

Regardless of the speaker, the overlap with the headline is remarkable.

------
oxryly1
This is an interesting method of building resiliency -- or anti-fragility --
into a complex system without adding complexity via a system of feedback for
each component (or some other such cleverness).

(I.E.: Have an overarching "intense activity" timer or measuring device signal
that the system is likely to suffer breakdown... just because it probably
will.)

The key intelligence here comes from the fact that the human fatigue system
evolved alongside the human organism, and thus has millions of years of
results built in. As a result it's fairly accurate.

~~~
cpncrunch
I suspect it has been around quite a while in evolutionary terms, and isn't
just in humans. All animals need to be careful that they don't overheat, go
without water, break a bone, etc. (However if another animal is chasing you,
it makes sense to turn off the inhibiting signal). The brain regions involved
are common to many animals AFAIK.

------
cel1ne
I'm doing rather exhausting martial arts, which includes doing all movements
at exact the speed in which the trainer counts.

There were moments where I felt I couldn't proceed and was exhausted. When
telling that to my trainer he, correctly, said: well your muscles aren't
shaking under load, so you can't be out of energy yet. After a pause of 10
seconds I was able to go on.

In my experience most physical fatigue can be countered by proper, regular and
deep breathing during movement. It seems to be an oxygen-distribution problem.

~~~
erikb
never forget that a different conclusion can also come from a different input.
Maybe your understanding of fatigue is not the same as the author's. You could
already see two definitions when comparing yours with your trainer's, right?

------
im3w1l
2012

~~~
duerrp
I don't know why this is down... the article is from 2012.

------
known
Is it same for procrastination?

~~~
cpncrunch
Possibly this might explain procrastination:

[https://www.researchgate.net/profile/Maarten_Boksem/publicat...](https://www.researchgate.net/profile/Maarten_Boksem/publication/51426280_Mental_fatigue_Costs_and_benefits/links/0f31753a54b2b691ba000000.pdf)

It seems to involve the same brain regions that Noakes identified as being
involved in physical fatigue. However rather than protecting against damage,
its function appears to be to protect against unnecessary expenditure of
energy.

