There are numerous studies that have addressed the relationship between mental health and physical activity in recent decades. We can tighten the relationship a little and focus on the relationship between walking and depression and its symptoms, but we will still encounter a problem: an abundance of experiments and analyzes dealing with the topic, some with mutually contradictory results.
Establishing science. To address this mess, a team of experts has made a meta-analysis around this topic, a quantitative study carried out based on previous studies. They thus observed that, taking the scientific literature as a whole, these analyzes indicated a negative relationship between how much we walk and the appearance of symptoms associated with depression.
The study was led by researchers from the University of Castilla la Mancha.
This “study of studies” was based on a systematic review of the scientific literature in order to find the relevant analyzes published to date (May 2024 in this case). From this search, they found 33 investigations observational studies that totaled 96,173 participants spread across 13 different countries.
Estimating a relationship. Based on the results obtained in previous research, the team responsible for this new study obtained new estimates on the relationship between the steps taken and the appearance of depressive symptoms. On the one hand, was observed that people who walked at least 10,000 steps a day showed fewer depressive symptoms than people who walked 5,000 or fewer.
On the other hand, they calculated that an increase of 1,000 steps a day was equivalent to a 9% reduction in suffering from these symptoms. Details about the methodology and results of this metaanalysis were published in an article in the magazine JAMA Network Open.
Caution in interpretation. Interpretation of the results requires a certain degree of caution. The reason is that this type of quantitative studies are good at detecting correlations between variables, but their ability to establish cause-effect relationships is limited since They are usually cross-sectional studiesso it largely depends on the type of studies that are included.
Establishing a cause-effect relationship in this case is especially difficult since the inverse relationship is true: having depression will make us less likely to walk, so this fact already conditions the existence of a correlation between the variables.
“This study cannot tell us if [caminar] prevents depression. It just shows that people who are less depressed walk more, but of course that may just be because they are happier and more active. In fact, inactivity is counted as a symptom of depression (…). “It may well be that exercise relieves depression, but I’m afraid this study provides no evidence that this is the case,” indicates David Curtisfrom the Institute of Genetics at University College London, who was not involved in the study.
Good advice. Brendon Stubbs, of the National Institute for Health and Care Research, share a similar opinion. “While there is a clear association between higher step counts and fewer depressive symptoms, we cannot be sure that walking reduces depression, as most studies only look at one point in time.”
However, this possibility cannot be ruled out either. “The results align with existing evidence that physical activity benefits mental health,” adds Stubbs. That is why maintaining an active life is still recommended if we want to reduce our probability of suffering from this type of problem or, if we do, to alleviate its impact.
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Image | Cristina Gottardi