HR4RS stamp
Libya Munoz Aguilera
This team, made up of different research groups from various universities, including the Rey Juan Carlos University, has carried out a qualitative evaluation of the evidence available to date, as well as a quantitative analysis of the data extracted from it and from which have obtained the following results.
In the first place, in this work we have reviewed the methodology applied in a total of 24 meta-analyses that include only controlled studies with groups of healthy people chosen at random (randomization controlled studies). Despite the fact that most of them generally confirm a positive effect of physical exercise, this team has detected considerable methodological deficiencies, such as few common sources among them and some added very selectively. In addition, low statistical power has been observed in studies controlled by randomization, as well as publication bias and great heterogeneity in the data and decision-making regarding the analysis performed.
Regarding the quantitative analysis of the data -from 109 randomized controlled studies, in which more than 11.200 healthy people between the ages of 6 and 80 were treated-, the research team has verified a substantial difference with respect to the original results. The positive effects of physical exercise on cognition that were initially concluded in the studies analyzed appear reduced throughout the age range once the effect of moderating factors is taken into account, such as publication bias, individual performance differences at start of the intervention and the type of activity selected among the control groups (active or passive forms). The latter is a fundamental aspect to take into account when avoiding problems in the methodology such as the placebo effect in the people studied.
“The findings emphasize the need for caution when establishing a direct and generalized causal relationship, since, according to our results, there is currently still a limited accumulation of methodologically sound and theoretically sound evidence to elucidate the true impact of physical exercise on cognition. in healthy people," says Antonio Luque, a researcher at the Sports Science Research Center (CIDE) of the URJC and co-author of the article published in the magazine Nature Human Behavior.
Therefore, it is possible that the conclusions drawn from part of the meta-analytic reviews available to date may not be the best representation of the real effect of the evidence accumulated to date, although this does not mean that physical exercise does not have potential beneficial impacts on cognitive functions of healthy people.
a new paradigm
The studies carried out to date are logistically very expensive, involve few participants and analyze short periods of time. For this reason, observational or longitudinal studies in large populations could help to discern the potential benefits of physical exercise on cognitive function, guaranteeing follow-up of people over years (instead of a few months) and, therefore, , obtaining a better opportunity to detect long-term changes, as well as determine the specific role of different mediating and moderating factors in this link.
In addition, developing more comprehensive theoretical models around the mechanisms that underlie this relationship between physical exercise and cognition would be of great relevance. That is, to reorient the current reductionist approach that indicates that the mechanisms underlying these benefits come merely from physiological processes at the molecular and cellular level, towards an approach that encompasses the entire spectrum of contextual complexity involved in the practice of physical exercise. It is a multifactorial phenomenon, where other factors such as the cognitive and social enrichment inherent in certain sports practice contexts, as well as behavioral and socio-emotional factors derived from the acquisition of physically active behavior patterns (for example, the quality of sleep , eating habits, stress level, mood, etc.), can directly or indirectly moderate the idiosyncrasies of this bond.
It is also important to take into account that this study has focused exclusively on the healthy population, and it is of vital importance to assess the limitations that this may produce when applying the conclusions obtained to people with diseases or limitations, such as those who suffer from some type of cognitive deterioration, Alzheimer's, among other pathologies.
In this sense, the standardization and simplification of experimental designs that facilitate greater replicability and increased statistical power, as well as the use of adequate control groups and initiatives such as pre-registration, could be useful in facilitating progress in this field of research. It is key to focus on this, since "a collective effort is required to promote transparency, openness, and reproducibility in science, as an irrefutable way to achieve solid empirical evidence," concludes Antonio Luque.
Currently, this line of research continues to be developed from the Center for Research in Sports Sciences (CIDE) through the EXER-NIBS project, financed by the Community of Madrid within the framework of the multi-year agreement with the Rey Juan Carlos University in its line Program of Stimulus to the Investigation of Young Doctors.