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A comment on Association between physical exercise and mental health: a cross-sectional study. Parent comment

Re:Association between physical exercise and mental health: ... by vanderZwan on Friday August 10, 2018 @02:00PM (#17735469)
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

[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...

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

[2] https://ki.se/en/news/how-physical-exercise-protects-the-bra...

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

[ Parent | on HN ]
Re:Association between physical exercise and mental health: ... by jessriedel on Friday August 10, 2018 @03:14PM (#17736012)
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.

[ Parent | on HN ]
Re:Association between physical exercise and mental health: ... by vanderZwan on Friday August 10, 2018 @04:06PM (#17736352)
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/

[1] https://scholar.google.de/scholar?hl=en&as_sdt=0%2C5&q=Skele...

[ Parent | on HN ]
Re:Association between physical exercise and mental health: ... by jessriedel on Friday August 10, 2018 @08:18PM (#17737589)
> 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.

[ Parent | on HN ]