健康：定期的な運動が認知機能に及ぼす好ましい影響はごくわずかかもしれない

There is little evidence for a positive relationship between regular physical exercise and improved cognition in healthy people, according to an umbrella review of 24 meta-analyses published in Nature Human Behaviour. The findings do not rule out that exercise may have potential benefits for cognition in healthy people, but highlight that there is currently limited evidence to support these claims.

Regular exercise is believed to not only have positive effects for physical health, but also to positively affect cognition and cognitive performance. These findings have informed public health policies, and some institutions currently recommend regular exercise as a means to maintain a healthy cognitive state.

Luis Ciria and colleagues reviewed 24 meta-analyses that detailed 271 primary studies before focusing on 109 studies encompassing 11,266 healthy participants in total. Their review was limited to studies that detailed randomized control trials, which are commonly used to ascertain causal links. The authors found that initial small, statistically significant positive effects of physical exercise on cognition disappeared after accounting for potential moderators (such as differences among the control groups and baselines of the studies) and correcting for publication bias. The authors stress that their findings do not suggest physical exercise does not have positive effects on cognitive functioning at all, or that it might be harmful for cognition. However, they argue that caution should be exerted when stipulating a causal link between exercise and cognition, as robust causal evidence is currently lacking.

They conclude that the benefits of physical exercise — especially with regard to physical health — are in themselves sufficient to justify evidence-based public-health policies to promote its regular application in people’s daily lives.