
Association between physical exercise and mental health: a cross-sectional study - happy-go-lucky
https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(18)30227-X/fulltext
======
jessriedel
This was a cross-sectional study. Here's an opposing result for anxiety and
depression:

> Testing Causality in the Association Between Regular Exercise and Symptoms
> of Anxiety and Depression

> Context: In the population at large, regular exercise is associated with
> reduced anxious and depressive symptoms. Results of experimental studies in
> clinical populations suggest a causal effect of exercise on anxiety and
> depression, but it is unclear whether such a causal effect also drives the
> population association. We cannot exclude the major contribution of a third
> underlying factor influencing exercise behavior and symptoms of anxiety and
> depression...

> Setting: Causal effects of exercise were tested by bivariate genetic
> modeling of the association between exercise and symptoms of anxiety and
> depression, correlation of intrapair differences in these traits among
> genetically identical twins, and longitudinal modeling of changes in
> exercise behavior and anxious and depressive symptoms.

> Results: Cross-sectional and longitudinal associations were small and were
> best explained by common genetic factors with opposite effects on exercise
> behavior and symptoms of anxiety and depression. In genetically identical
> twin pairs, the twin who exercised more did not display fewer anxious and
> depressive symptoms than the co-twin who exercised less. Longitudinal
> analyses showed that increases in exercise participation did not predict
> decreases in anxious and depressive symptoms.

> Conclusion: Regular exercise is associated with reduced anxious and
> depressive symptoms in the population at large, but the association is not
> because of causal effects of exercise.

[https://jamanetwork.com/journals/jamapsychiatry/fullarticle/...](https://jamanetwork.com/journals/jamapsychiatry/fullarticle/210112)

There's a huge bias in popular reporting toward studies concluding that
interventions are helpful.

~~~
vanderZwan
The thing is, since a few we actually know now how exercise helps: it builds
_resilience_ against depression[0][1]. The press release from the Karolinska
Instituted website[2] explains it fairly well, but in short: when you're
stressed, you produce kynurenine. How kynurenine works precisely is unknown,
but what _is_ clear is that having chronically elevated levels of it can
induce all kinds of mental illnesses. Skeletal muscle creates _kynurenine
aminotransferase_ (KAT), an enzyme which breaks it down.

The subtlety here is that this building _resilience_ is not the same as fixing
the _causes_ of depression[3].

(I'm a bit surprised this research isn't mentioned in these papers)

[http://science.sciencemag.org/content/357/6349/eaaf9794](http://science.sciencemag.org/content/357/6349/eaaf9794)

[0] _Skeletal Muscle PGC-1α1 Modulates Kynurenine Metabolism and Mediates
Resilience to Stress-Induced Depression_ ,
[https://www.cell.com/cell/abstract/S0092-8674(14)01049-6?cod...](https://www.cell.com/cell/abstract/S0092-8674\(14\)01049-6?code=cell-
site)

[1] _Kynurenines: Tryptophan’s metabolites in exercise, inflammation, and
mental health_ ,
[http://science.sciencemag.org/content/357/6349/eaaf9794](http://science.sciencemag.org/content/357/6349/eaaf9794)

[2] [https://ki.se/en/news/how-physical-exercise-protects-the-
bra...](https://ki.se/en/news/how-physical-exercise-protects-the-brain-from-
stress-induced-depression)

[3]
[http://pbfcomics.com/comics/treatment/](http://pbfcomics.com/comics/treatment/)

~~~
jessriedel
That theory would seem to contradict the study I cited, no?

Both papers you cite are by the same group, and I don't think the results
represent a consensus of the experts.

~~~
vanderZwan
Not necessarily: in another study it was shown that kynurenine levels went
back to original levels in patients who only exercised[0].

> _Conclusions: Physical exercise positively affects mood and cardiovascular
> fitness, but does not lead to long-lasting changes in plasma levels of
> kynurenine and KYNA in patients affected by mild-to-moderate depression._

So that would suggest that the body just reaches a new equilibrium. Again, the
point is that _resilience_ does not fix _causes_ \- it could be that this is
similar to trying to fix traffic jams with more roads; the only real fix is to
get rid of the cars as much as you can (after which having an extra lane can
make traffic go smoother).

> _Both papers you cite are by the same group, and I don 't think the results
> represent a consensus of the experts._

IIRC, that kynurenine does _something_ is apparently well-established, and not
just by this group. Also, that first paper has quite a few citations, you can
check for follow-up research on Google Scholar[1]

[0]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384718/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384718/)

[1]
[https://scholar.google.de/scholar?hl=en&as_sdt=0%2C5&q=Skele...](https://scholar.google.de/scholar?hl=en&as_sdt=0%2C5&q=Skeletal+Muscle+PGC-1%CE%B11+Modulates+Kynurenine+Metabolism+and+Mediates+Resilience+to+Stress-
Induced+Depression&btnG=)

~~~
jessriedel
> So that would suggest that the body just reaches a new equilibrium.

This is another degree of freedom in the theory, right?

I mean, this could all be true for all I know, but as an outsider I think this
falls into the category of stuff I can't judge, and (like a thousand other
theories investigated by experts and published in impressive places like
_Science_ ) hasn't yet risen to the level of consensus.

------
ec109685
How does a study like this control for the fact that if you are depressed, you
might not want to exercise that day? And thus it’s mental health that drives
how much you exercise, not the other way around?

~~~
jpmoyn
The study itself addresses that they didn't prove causality between exercise
and reduced symptoms of anxiety and depression

~~~
posterboy
They are not very careful to avoid implying the expected outcome, though,
which should be understandable as it refers to common wisdom. e.g. "more is
not always better" is part of the interpretation, nevertheless they don't
imply any causative effects (on the landing page, at least; didn't read the
paper).

In that sense, if feeling too depressed for extreme sport, maybe a walk ever
now and then should at least not be neglected.

------
SketchySeaBeast
This is sure to quickly fill with personal anecdotes, I can attest to
experiencing this phenomena myself, but I wonder what we can do with this
information? I think it's already in the "everybody knows" category, so how do
we get those who need it the most to take advantage of it? The extreme
presentation of these conditions typically impedes one from becoming
physically active, thought I do look forward to the success that I'm sure will
be the first soccer league for agoraphobics.

~~~
raverbashing
I think most people associate "physical exercise" with _having to spend an
hour at the gym_ or something similar.

What they should be thinking is: going for a walk around the block, not
getting the car for close by errands, not taking the elevator, going for a
bike ride, etc

~~~
Broken_Hippo
See, this is some of my own problem. I personally despise going for a walk for
the sake of going for a walk. The same for a bike ride. The only times I've
enjoyed such things is when part of my unhappiness was at home and it was one
of the few escapes available. I don't find these fun at all. Doing actual
exercise sounds dreadful and embarrassing. Not to mention that finding basic
gear is expensive and hard to find (I'm just talking about a sports bra here -
unfortunately, if you are thin with breasts, these get incredibly hard to find
and expensive and often must be mail-ordered, which makes them risky).

Yet I'll walk _to_ anywhere within a half an hour's walk. I'll do that daily.
Grocery store? walk. I'll go longer at times. I'll take the stairs. I'll go
out hiking and walking to _see_ something or _do_ something.

Unfortunately, if I have nothing to see or do - no work or lack the means to
do something - I rarely do these things. These have generally been the times
when my mental health is worst as well (though that trend has changed the last
few years). It makes me despise these sorts of reports.

~~~
phakding
I totally agree with you. I go to gym and weight train 3 days a week and I
spend one day running as far as I possibly can (8-10 mile range). If someone
asked me to go for a walk, I would just slouch down in my sofa and ignore
them. I hate walking without purpose and as an exercise it does pretty much
nothing.

~~~
devilshaircut
Personally, I hate exercising but I do about 90 minutes of high intensity
cardio every day (with no end goal like grocery shopping; just for the sake of
exercise). It's masochistic and I wish I were the type of person who actually
enjoyed it.

For me, it just took having the self-control to commit to an exercise regime.
Eventually it became easier because I track my exercise and having a break in
it (even if I am traveling or on vacation) feels really bad.

I doubt it would work for everyone, but I think it was necessary for me
because I live in a city and even if I walked everywhere (which I do), I would
never get enough exercise to offset 8-hour days of sitting at a computer desk
writing software.

------
themodelplumber
I personally find that exercise only contributes to good mental health
outcomes when it is part of a system that monitors and directly, daily,
addresses issues of physical exhaustion. Experiencing exhaustion and a desire
to push through it was my personal #1 link to depression and anxiety. I found
that just laying in bed and relaxing has a much higher likelihood of
vanquishing my depression and anxiety than exercise ever did, and exercise,
even a simple walk, can actually make the symptoms worse by contributing to
the exhaustion.

This is _my own analysis and experience_, of course, so YMMV. There are
additional important approaches to anxiety, like identifying stressors that
need to be addressed (situations, goals, relationships, etc.) and attending to
various facets that contribute to a feeling of purpose and promise. But after
learning to look at my symptoms through the lens of "exhaustion" (whether it
be productivity exhaustion or fitness-induced) I no longer suffer from chronic
severe anxiety and depression, and my psychiatrist long ago pronounced me
cured. Some people here may benefit so I share this in case it helps.

~~~
natalyarostova
Interesting. Lying in bed is pretty much my #1 link for depression and anxiety
(unless I'm sleep deprived and need to sleep).

~~~
121789
Same here. And exercise immediately cures it. I wonder why OP is physically
exhausted so much

~~~
themodelplumber
Don't limit it to "physically", just imagine a person who pushes themselves
really hard in all aspects of life. That pretty much describes who I was.
Beyond a productive person, more like a natural stress-bringer.

~~~
collyw
Personally I find physical exhaustion, from a long hike for example, a lot
more pleasant than mental exhaustion. The first feels positive (helps me sleep
well), the second feels negative.

------
taneq
I'm interested to see how VR affects overall mental health among gamers. There
seems to be some crossover between heavy duty gamers and mental health
struggles (just from my own observation) and VR is starting to be a natural
progression for gaming. And VR gaming is often a real work-out, focusing on a
lot of movement as well as physical dexterity.

~~~
prophesi
I'm interested in this as well. I had a friend play Beat Saber for 3 hours
straight, burning literally thousands of calories. He said he felt amazing for
the rest of the day.

On the flip-side, I personally experienced some serious post-binge depression
after playing Talos Principle VR for a few hours. It's not very physically
engaging, with a somber atmosphere throughout. I felt so weird taking off the
headset and jumping back into reality.

Though I think both scenarios just go to show how powerful VR could
potentially be in the medical field.

~~~
always_good
Let's be honest, though. He didn't burn thousands of calories. You are
underestimating how efficient the human body is.

~~~
taneq
Actually I think this is really important. I don't have any science to back
this up but I feel like the human body actually changes its tradeoff between
efficiency and instantaneous performance based on some so-far-undescribed
factor.

------
hi41
For many months now I have been bad at paying bills, filing tax etc due to
anxiety and depression. It is like paralysis. But reality does not wait for
you. There are consequences like fines and court orders. How have you overcome
this? I feel I will be happier if I can manage my duties better.

~~~
kranner
I’ve noticed this pattern in myself that I like to call Automatic Pointless
Resistance which is especially active when I’m anxious. I overcome it by
completely ignoring my feelings and getting started on tasks regardless of how
little I want to do them, or how much I think I’m going to screw them up.
Sometimes the disconnect is profound, my brain just doesn’t want to do
something but my body knows what to do. Even if it’s something mentally
involving like filing taxes, I just ignore any thoughts that say I must be
doing it wrong, I should stop and plan it better, etc. And before I know it,
the task is well underway and I’m often even enjoying it.

------
itschekkers
Original Article author here - happy to help with any questions people have.

Also sorry about the paywall - you can get the article either through sci-hub
here [http://sci-hub.tw/10.1016/S2215-0366(18)30227-X](http://sci-
hub.tw/10.1016/S2215-0366\(18\)30227-X) or you can email me and i'll send you
a copy direct!

~~~
Kyrztyn
Awesome.

Question:

Why are you wasting your time?

Do you wish to apply a blanket cure for the unknown multitude causes of mental
health issues?

Why do you think reductions in the self reported “mental health” of the
general population is useful for people who have been hospitalized with mood
disorders?

Don’t you think that people who lie about how much exercise they do also might
be lieing to themselves about their mental health?

~~~
itschekkers
1- surely we're allowed to waste our own time if we like!

2- nope, and actually my entire research agenda has been around helping people
find a treatment that is most likely to work for them specifically! (we also
founded a company to bring the research to market- springhealth.com)

3- that is beyond the scope of the paper, and we didnt use the word
hospitalized once

4- yep, and thats a good example of one of the pitfalls of self-reported
surveys. in general, i am a bit less cynical and in our experience, most
people aren't filling out surveys to intentionally lie or sabotage.

hope this helps!

~~~
rrggrr
You didn't deserve that response. Good job on the paper and keep up the good
work. Your findings are supported by other research as you already know.

~~~
itschekkers
thanks! <3

we've had a wonderful positive response to this article, and people are
overwhelmingly excited and motivated to try and exercise more because of it
(even at relatively lower intensities or volumes -- every little helps). even
if we are extremely cynical and say theres zero benefit of exercise for mental
health, then people will still be getting known improvements regarding
diabetes, stroke, cardiovascular disease. Nobody is advocating for exercise at
the expense of alternative treatments like meds or therapy, this really is
just a (potentially large) extra benefit.

~~~
Kyrztyn
Aw, hearts!

:/

You established ZERO causality in your study! How can you even say you are a
scientist and say this has a (potentially) large benefit?!

And you did not even distinguish between mental health and mental illness.

The fact that you are excited that you got a “positive response” from this
article just tells me you are a neoliberal shill.

------
Kyrztyn
This study was flawed from the start. They asked people if they were ever
“diagnosed” with depression when there is no clear cause of depression.
Depression can be lifelong, short term situational, caused by drugs, etc.

It also relied on self reported physical activity! Ha!

It is worthless to extract anything regarding mental heath and exercise from
this study.

~~~
markroseman
I'd consider the value to be motivational ammunition for an intervention that
generally has few downsides and multiple possible benefits for the person
affected. Your point about stigma does counterbalance that somewhat.

In other words, would I put the overview on the coffee table in my wife's
office (she's a psychiatrist) for her patients to see? Yes.

~~~
Kyrztyn
They did not establish causality in the study, yet you would put it out for
sick people already stigmatized and thinking they are “lazy”, “just need to
get out of bed”, etc as another burden for them to carry?

Are you a sadist?

Let me give you a personal anecdote. I suffered depression and anxiety and
fatigue for years. I tried to be active but it made me feel worse. Turns out I
had late onset partial biotinidase deficiency. I take biotin, my depression
and anxiety are gone and now I can work out like a normal person.

What good does this study do for people like me and the probably hundreds of
thousands of people like me? I would in fact it harms people like me because
it lays a simple cure over a complex and diverse issue.

~~~
markroseman
In this or anything else, exercise isn't suggested as a cure.

Almost without exception, the people she sees are looking for ways to help
move themselves forward. By the time they get here, they realize (and it's
part of the education that goes with the practice) that mental illness is
extremely complex, not every treatment helps everyone, and there's no single
magic bullet. And yes, serious metabolic workups are a big part of the
practice.

So while I appreciate your perspective, I take issue with the claim that (in
this context) it is suggesting laziness as a cause for their illness, or
sadism on my part.

~~~
Kyrztyn
I’d be interested if your wife tests for Biotinidase Deficiency...? There are
no “serious metabolic work ups” for mental health. Sure, they test thyroid,
maybe iron and B12 if you press them. But beyond that?

I am telling you, as a person who suffered from suicidal depression, that
seeing a pamphlet like that in the past would make me feel worse, not better.
But why listen to me? I am only the patient.

