Review An umbrella review of randomized control trials on the effects of physical exercise on cognition 2023 Ciria et al

Pre-print (free access)
Abstract

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here, we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reported a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias, and large variation in combinations of preprocessing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows a small exercise-related benefits (d = 0.22) that became substantially smaller after accounting for key moderators (i.e., active control and baseline differences; d = 0.13), and negligible after correcting for publication bias (d = 0.05, 95% CrI [−0.09, 0.14]). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

https://www.biorxiv.org/content/10.1101/2022.02.15.480508v4

 

Always, though, is that the issue is made over recreational exercise. Lots of people are very physically active at their work, in some cases it grinds down the body so much that it causes significant health issues later on, and clearly people who do backbreaking labor are not in better health than those who have cushy middle class jobs, in large parts because socioeconomic determinants of health are far more significant than physical exertion.

Everything being marketed as good for mental health is always recreational: listen to birds in the forest, enjoy quiet music, meditate, finger-paint with friends, do some light exercises in a nice quiet natural environment. Sometimes it's exerting, but it's always recreational. They're always recreational and centered around rest, around not working, around not exerting. It's never about the actual exercises, it's the recreational aspect and its full implications: people who have the luxury to go on regular vacations like this have better socioeconomic factors than those who don't.

That's truly the most amazing thing about this: they keep finding that it's enjoying life and taking time off obligations that makes people happier, and yet their conclusions is always to do more: exercise more, harder, work more, harder, do more stuff, which is the opposite of what their own research shows.

Do people with mobility issues making exercise impossible but otherwise have no other health problems do worse cognitively on average than people who simply move around at all? Probably not. Actually finding this out is possible, but this is never how it's done, instead it's always wishy-washing new age stuff that, in the end, emphasizes that recreation is important, but finds that work will set people free of illness, a conclusion forever in search of a problem that isn't lack of itself. Madness.

 

(Merged) Final paper - paywall

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan.

Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval −0.09 to 0.14).

These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

Paywall, https://www.nature.com/articles/s41562-023-01554-4

 

Will no doubt be a horse with high cognitive functioning.

 

Almost every time I see a paper on reddit in psychology, sociology or other fields of research using associative data, there's always numerous comments about how correlation doesn't imply causation.

Except when it's about mindfulness stuff or the various benefits of exercise and wishy-washy mental health stuff. Sometimes it's there, but you can see that this is something people badly want to be true and that the normal skepticism just goes out the window. Although it seems to be happening more these days, as the evidence grows thinner and the claims have to morph to keep the beliefs. The hype is not so strong in the general population as it was only a few years ago.

And I think that most people want it to be true not really for themselves, most people don't do enough even though they believe in it, so much as it gives that universal excuse to blame other people for not doing what they aren't doing either. Although I'm observing a recent trend where it's all about tiny bursts of activity having the same positive impacts, something like just 30 minutes on the week-end is just as good as going to the gym every day of the week. The claims are slowly reducing in how much investment people have to make, but the conclusions remain the same.

And the wellness industry, and its biopsychosocial counterpart, has much to blame for it. So does the medical profession at large for massively overhyping advice they usually don't follow themselves either.

Humans love to blame victims for their own misfortune. Just as the doctor ordered. But the asymmetry of bullshit is vastly unequal, it'll be years before those overhyped claims being debunked has any impact.