Exercise as it relates to Disease/Sedentary behaviour and its impact on mental health in school aged children

== What is the Background to this Research? == Sedentary behaviour is defined as any waking state that has an energy expenditure rate of less than 1.5 METs, including writing, typing or desk work while sedentary or seated. In a climate that sees a shift to a more sedentary lifestyle, whether it be work, transport or recreation related, sees the population faced with a range of debilitating health issues. Some of these health risks include; lower cardiorespiratory fitness, higher BMI, low HDL count, and an increased risk of abdominal adiposity. While the link between physical health and sedentary behaviour is well documented, a gray zone exists about the potential risk to mental health, especially in children, as mental health has a high prevalence into adulthood. Hence a recent systematic review looked at this link, and in early 2015 published their findings that investigated the relationship between mental health and sedentary behaviour in school aged children.

Where is the Research from?
The review was conducted by researchers from the Institute for Therapy and Health Research (ITF-Nord), in Kiel Germany. It is published in Preventative Medicine, a highly rated journal and was obtained through open access.

What kind of Research was this?
A systematic review, which is a review of literature which aims to compile, select through criteria, and identify information that is of high quality in an attempt to answer the posed question.

What did the Research Involve?
In this review, six online databases; MEDLINE, EMBASE, PsycINFO, PsycARTICLES, CINAHL and SPORTDiscus, as well as libraries and reference lists that were included in the existing literature were searched for eligible studies. After duplicates, 5,272 records existed. These records had to meet a detailed criteria to be considered in the review, this included; age, design, publication, accurate measures, and language. On top of this, they were rated on quality and risk of bias. After this criteria, 91 studies existed. Unfortunately the criteria is far too thorough, washing down such a huge amount of literature to a select few studies removes a lot of valuable data that could give this review more weight when making claims. This becomes a bigger problem when looking at the results section for separate mental health indicators, with some inferences being made on 8 studies alone. Although the studies admitted to the review are of high quality, too much quantity is sacrificed to meet this standard.

What were the Basic Results?
The results from the systematic review are very mixed depending on the mental indicator being observed. An inconclusive amount of evidence was found to support a link between sedentary behaviour and anxiety symptoms, depressive symptoms, self-esteem and eating disorders. Unfortunately, the bulk of the reviewed material looked at these topics. However, there seems to be a strong amount of evidence showing a link between sedentary behaviour and hyperactivity and inattention problems, with only one article disagreeing. There also seems to be a strong relationship between sedentary behaviour and overall well-being and quality of life, even though 4 of the 15 reviewed articles found no evidence, with 1 of these articles only applying to girls. As well as a relatively positive correlation for internalising problems.

How did the Researchers Interpret their Results?
The researchers say there is strong evidence that high levels of screen time were associated with hyperactivity, inattention problems as well as internalising problems, less psychological well-being and perceived quality of life. In regards to depressive symptoms, self-esteem, eating disorders, and anxiety, mixed results led the authors to draw no conclusion. Interestingly, the researchers say that if lower quality papers included in the study were ignored, and only higher quality ones taken into account, then a correlation between self-esteem and sedentary behaviour would be found.

What Conclusions should be taken away from this Research?
The systematic review has produced evidence to support a link between sedentary behaviour and symptoms related to; hyperactivity, inattention problems, internalising problems, well-being and quality of life. This evidence is reflective of that produced in past reviews. These findings solidify the notion that a sedentary lifestyle moves beyond the physical implications and effects our mental health.

What are the Implications of this Research?
While the evidence is there to suggest a link between sedentary behaviour and mental health, the incredibly ruthless attention to filtering the articles may be the reviews greatest weakness. Over 5,000 peer-reviewed articles scratched down to 91 is somewhat of a problem - articles that could of proven a link between mental health problems such as self-esteem, eating disorders or anxiety, may have been lost amidst the huge amount of papers discarded, and these indicators were instead reported as inconclusive. Therefore, future reviews need to be focused on proving a very specific correlation between sedentary behaviour and a specific mental health problem; and a larger amount of articles need to be included without sacrificing quality. As for research there simply is too many cross-sectional studies, and not enough longitudinal studies to measure the causality of sedentary behaviour and mental health. This review sets this correlation on an unsettling path - due to the living environment posed by modern society, the shift to sedentary behaviour is only going to become more apparent, and the evidence that shows this may affect our mental health is disturbing. While it is important to abstract more evidence through reviews, or well conducted longitudinal studies - perhaps the real focus needs to be intervention methods. The perception of exercise needs change, too often is it discarded for being 'too strenuous' or as 'recreation', while it does have this duality, it needs to start being seen and broadcasted as a preventative and protective measure against a multitude of physical and mental problems. If this is achieved, the problems posed by sedentary behaviour can be cushioned, or perhaps even eliminated.