4 ms·

This was a cross-sectional study. Here's an opposing result for anxiety and depression: > Testing Causality in the Association Between Regular Exercise and Sy

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/210112 https://jamanetwork.com/journals/jamapsychiatry/fullarticle/... There's a huge bias in popular reporting toward studies concluding that interventions are helpful.

markroseman 8y ago
Few academics stake their careers on papers saying that X does fuck all (unless everyone already things X is amazingly effective)
- DanBC 8y ago
  Cochrane Collaborations. https://www.cochrane.org/CD004366/DEPRESSN_exercise-for-depression https://www.cochrane.org/CD004366/DEPRESSN_exercise-for-depr... > Exercise is moderately more effective than no therapy for reducing symptoms of depression. [...] > The reviewers also note that when only high-quality studies were included, the difference between exercise and no therapy is less conclusive.
deleted 8y ago
[deleted]
duxup 8y ago
That and I wonder if there is a spiraling sort of effect where if you have mental health issues you might feel tired as it is, so you don't exercise.... but I'm not sure that means that the exercise is the issue... just the result. Let alone populations like the working poor who have little time in their lives for things like exercise, but growing mental illness issues.
- ralusek 8y ago
  Mood-changing exercise can take as little as 3 minutes. If I do 2 minutes of jumping jacks and 30 pushups in the morning, my day is dramatically different. Saying that "the poor don't have time for exercise" reminds me of a similar, harmful claim that "the poor can't afford to eat healthily." Bag of kale is $2, massive bag of spinach is $4, massive bag of carrots is $3, bag of of onions is $5, massive bag of potatoes is $5... When asked about their obesity, many poor have responded with that same idea, that "healthy food is expensive." It's important to recognize that simply saying things repeatedly at a societal level is enough to actually negatively impact the people it was meant to defend.
  - duxup 8y ago
    The working poor certainly don't have a lot of time... that's not a myth. Pretending it must be like some other issue is not helpful, just as you describe the other issue.
  - DanBC 8y ago
    > Mood-changing exercise can take as little as 3 minutes. If I do 2 minutes of jumping jacks and 30 pushups in the morning, my day is dramatically different. You know this is what homeopaths claim, right?
    - Kyrztyn 8y ago
      Did you mean sociopaths?
    - taneq 8y ago
      They're not magically wrong about everything, if they were then that'd be as useful as being right.
0x62c1b43e 8y ago
They have a section discussing why this paper might seem to contradict other studies showing a causal link: > This outcome seems at odds with findings from randomized controlled trials in clinical and population samples indicating that regular exercise can relieve symptoms in subclinical individuals and in patients diagnosed as having an anxiety or depressive disorder. To understand the different outcomes of both types of study, it is crucial to make a distinction between the effects of prescribed and externally monitored exercise in selected subgroups and the effects of voluntary leisure-time exercise at the population level. Only voluntary leisure-time exercise is influenced by genetic factors, whereas the other type of exercise is environment driven. The absence of causal effects of voluntary exercise on symptoms of anxiety and depression does not imply that manipulation of exercise cannot be used to change such symptoms. It means that a population association, cross-sectional or longitudinal, cannot be used to justify exercise as a treatment without an actual randomized controlled trial. The possible difference in the antidepressant effects of prescribed vs voluntary exercise is consistent with findings from a recent study suggesting that the therapeutic effects of exercise are nonspecific to exercise. The antidepressant effects of exercise may only occur if the exercise is monitored and part of a therapeutic program. So it sounds like among twins, if one twin naturally exercises more by their own volition, that twin doesn't in general show less depression/anxiety than the other twin, which is evidence against exercise causally reducing depression/anxiety. However it sounds like it may still be that prescribed exercise as an intervention, beyond what an individual would naturally choose to do, and maybe only in conjunction with therapy, could still benefit an individual (and perhaps then only individuals with clinical symptoms). This study also does help by showing how the associative inverse relationship between exercise and depression in the general population seems to be from genetics influencing exercise, and not the other way around, and the important of a randomized control trial on exercise as an intervention.
vanderZwan 8y ago
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?code=cell-site 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 http://science.sciencemag.org/content/357/6349/eaaf9794 [2] https://ki.se/en/news/how-physical-exercise-protects-the-brain-from-stress-induced-depression https://ki.se/en/news/how-physical-exercise-protects-the-bra... [3] http://pbfcomics.com/comics/treatment/ http://pbfcomics.com/comics/treatment/
- jessriedel 8y ago
  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 8y ago
    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=Skeletal+Muscle+PGC-1%CE%B11+Modulates+Kynurenine+Metabolism+and+Mediates+Resilience+to+Stress-Induced+Depression&btnG= https://scholar.google.de/scholar?hl=en&as_sdt=0%2C5&q=Skele...
tryitnow 8y ago
Thanks for providing this study. This reminds me of the Iron Law of Evaluation: https://www.gwern.net/docs/sociology/1987-rossi https://www.gwern.net/docs/sociology/1987-rossi The Iron Law refers social program interventions but I think it is applicable to a lot of health interventions too. https://www.gwern.net/docs/sociology/1987-rossi https://www.gwern.net/docs/sociology/1987-rossi

markroseman 8y ago

Few academics stake their careers on papers saying that X does fuck all (unless everyone already things X is amazingly effective)

DanBC 8y ago
Cochrane Collaborations. https://www.cochrane.org/CD004366/DEPRESSN_exercise-for-depression https://www.cochrane.org/CD004366/DEPRESSN_exercise-for-depr... > Exercise is moderately more effective than no therapy for reducing symptoms of depression. [...] > The reviewers also note that when only high-quality studies were included, the difference between exercise and no therapy is less conclusive.

deleted 8y ago

[deleted]

duxup 8y ago

That and I wonder if there is a spiraling sort of effect where if you have mental health issues you might feel tired as it is, so you don't exercise.... but I'm not sure that means that the exercise is the issue... just the result. Let alone populations like the working poor who have little time in their lives for things like exercise, but growing mental illness issues.

ralusek 8y ago
Mood-changing exercise can take as little as 3 minutes. If I do 2 minutes of jumping jacks and 30 pushups in the morning, my day is dramatically different. Saying that "the poor don't have time for exercise" reminds me of a similar, harmful claim that "the poor can't afford to eat healthily." Bag of kale is $2, massive bag of spinach is $4, massive bag of carrots is $3, bag of of onions is $5, massive bag of potatoes is $5... When asked about their obesity, many poor have responded with that same idea, that "healthy food is expensive." It's important to recognize that simply saying things repeatedly at a societal level is enough to actually negatively impact the people it was meant to defend.
- duxup 8y ago
  The working poor certainly don't have a lot of time... that's not a myth. Pretending it must be like some other issue is not helpful, just as you describe the other issue.
- DanBC 8y ago
  > Mood-changing exercise can take as little as 3 minutes. If I do 2 minutes of jumping jacks and 30 pushups in the morning, my day is dramatically different. You know this is what homeopaths claim, right?
  - Kyrztyn 8y ago
    Did you mean sociopaths?
  - taneq 8y ago
    They're not magically wrong about everything, if they were then that'd be as useful as being right.

0x62c1b43e 8y ago

They have a section discussing why this paper might seem to contradict other studies showing a causal link: > This outcome seems at odds with findings from randomized controlled trials in clinical and population samples indicating that regular exercise can relieve symptoms in subclinical individuals and in patients diagnosed as having an anxiety or depressive disorder. To understand the different outcomes of both types of study, it is crucial to make a distinction between the effects of prescribed and externally monitored exercise in selected subgroups and the effects of voluntary leisure-time exercise at the population level. Only voluntary leisure-time exercise is influenced by genetic factors, whereas the other type of exercise is environment driven. The absence of causal effects of voluntary exercise on symptoms of anxiety and depression does not imply that manipulation of exercise cannot be used to change such symptoms. It means that a population association, cross-sectional or longitudinal, cannot be used to justify exercise as a treatment without an actual randomized controlled trial. The possible difference in the antidepressant effects of prescribed vs voluntary exercise is consistent with findings from a recent study suggesting that the therapeutic effects of exercise are nonspecific to exercise. The antidepressant effects of exercise may only occur if the exercise is monitored and part of a therapeutic program. So it sounds like among twins, if one twin naturally exercises more by their own volition, that twin doesn't in general show less depression/anxiety than the other twin, which is evidence against exercise causally reducing depression/anxiety. However it sounds like it may still be that prescribed exercise as an intervention, beyond what an individual would naturally choose to do, and maybe only in conjunction with therapy, could still benefit an individual (and perhaps then only individuals with clinical symptoms). This study also does help by showing how the associative inverse relationship between exercise and depression in the general population seems to be from genetics influencing exercise, and not the other way around, and the important of a randomized control trial on exercise as an intervention.

vanderZwan 8y ago

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?code=cell-site 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 http://science.sciencemag.org/content/357/6349/eaaf9794 [2] https://ki.se/en/news/how-physical-exercise-protects-the-brain-from-stress-induced-depression https://ki.se/en/news/how-physical-exercise-protects-the-bra... [3] http://pbfcomics.com/comics/treatment/ http://pbfcomics.com/comics/treatment/

jessriedel 8y ago
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 8y ago
  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=Skeletal+Muscle+PGC-1%CE%B11+Modulates+Kynurenine+Metabolism+and+Mediates+Resilience+to+Stress-Induced+Depression&btnG= https://scholar.google.de/scholar?hl=en&as_sdt=0%2C5&q=Skele...

tryitnow 8y ago

Thanks for providing this study. This reminds me of the Iron Law of Evaluation: https://www.gwern.net/docs/sociology/1987-rossi https://www.gwern.net/docs/sociology/1987-rossi The Iron Law refers social program interventions but I think it is applicable to a lot of health interventions too. https://www.gwern.net/docs/sociology/1987-rossi https://www.gwern.net/docs/sociology/1987-rossi