Exercise as it relates to Disease/The effects of resistance exercise training on anxiety

This is a critique of the article "The Effects of Resistance Exercise Training on Anxiety: A Meta-Analysis and Meta-Regression Analysis of Randomized Controlled Trials".

What Is The Background To This Research?
Basically defined, anxiety is an emotion characterised by an unpleasant state of inner turmoil or impending doom, often accompanied by nervous behaviour such as pacing back and forth, somatic complaints (e.g. stomach butterflies etc.), and rumination. Anxiety is the most common mental health condition in Australia. Anxiety affects approximately one quarter of Australians, at some point in their lifetime (1 in 3 women, and 1 in 5 men). According to the ABS National Survey of Mental Health and Wellbeing, 2007, 26.3% of Australians aged 16–85 have experienced an anxiety disorder. Using the 2007 statistic, that percentage equates to 4.96 million people today.

The statutory effects of resistance exercise training (RET) are well established, however, there is far less known regarding the effects of RET on mental health outcomes. While there is a large amount of consensus about the positive effects of aerobic exercise training (AET) on anxiety, a quantitative synthesis of RET effects on anxiety is needed.

About the article
This paper looks to collectively examine and consolidate data from 16 existing studies that were completed prior to 2017. The purpose of the meta-regression analyses reported in this article was to examine participant characteristics and features of the RET stimulus that may moderate, or influence, and ideally could be manipulated to enhance, the effect of RET on anxiety symptoms. The purpose of these analyses was not to test whether those variables help to explain the effects of RET.

Where Is The Research From?
The Analysis, published in Sports Medicine, compiles studies and results from 16 articles published prior to 2017. For an article to be included in the analysis, it had to fulfil the following criteria; English language peer reviewed publications, randomised allocation to either a RET intervention group or a non-active control group, and anxiety outcome measures at baseline (pre), and at mid- and/or post-intervention.

The articles that were included in this study are as follows:


 * 1) The influence of resistance exercise training on the levels of anxiety in ischemic stroke
 * 2) Effects of aerobic and resistance exercise in breast cancer patients receiving adjuvant chemotherapy: a multicenter randomized controlled trial
 * 3) The effects of strength training on strength and health-related quality of life in older adult women
 * 4) Effects of aerobic training, resistance training, or both on psychological health in adolescents with obesity: the HEARTY randomized controlled trial
 * 5) Effects of short-term exercise training on signs and symptoms of generalized anxiety disorder
 * 6) The efficacy of 12 weeks supervised exercise in obesity management
 * 7) The physiological and psychological effects of resistance training on Chinese obese adolescents
 * 8) Effects of strength and aerobic-based training on functional fitness, mood and the relationship between fatness and mood in older adults
 * 9) Psychological and physical benefits of circuit weight training in law enforcement personnel
 * 10) Low-load/ high-repetition elastic band resistance training in patients with COPD: a randomized, controlled, multicenter trial
 * 11) Effectiveness of home exercise on pain and disability from osteoarthritis of the knee: a randomised controlled trial
 * 12) Effects of an 8-week circuit strength training program on the body images and anxiety in untrained college students
 * 13) Comparison of high and moderate intensity of strength training on mood and anxiety in older adults
 * 14) The feasibility of progressive resistance training in women with polycystic ovary syndrome: a pilot randomized controlled trial
 * 15) Efficacy of a weight training program as a treatment for chemically dependent adults
 * 16) The effect of a strength training program on affect, mood, anxiety, and strength performance in older individuals

What Kind Of Research Was This?
The study is a meta-analysis. As opposed to a systematic review, which answers a particular, specific research question, a meta-analysis is a quantitative, formal, epidemiological study design used to summarise the results of a group of these studies, and derive conclusions about that body of research. Outcomes from a meta-analysis may provide a more accurate estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study included, if it where in it’s own.

What Did The Research Involve?
The authors derived 31 'effects' from the 16 studies. These effects were the independent variables in each intervention. Anxiety was found to be the primary outcome in 10 of the studies (23 of the effects pertained directly to anxiety).

'Hedges’ d' effect sizes were calculated for each effect. Put simply, effect size tells you how much one group differs from another (in this case RET vs. Control). Effect sizes were adjusted for small sample size bias and calculated so that a larger reduction of anxiety symptoms among those in the RET group resulted in a positive effect size. Meta-regression was used as the overall analysis tool for the effects.

What Were The Basic Results?
In regard to the 16 studies included, the average participant age was 43 ± 21 years, and 68% of participants randomised were female. The average intervention length was 11 weeks; and intervention frequency ranged from 2 to 5 days per week.

To give a brief summary of the cumulative results gathered by the authors, RET has a small-to-moderate statistically significant, positive effect on anxiety symptoms. The overall mean effect score (Δ=0.31) provides quantitative, measurable support for the anxiolytic effects of RET previously reported by O'conner et al.

Lowered anxiety symptoms found among RET participants in the reviewed studies, expressed as a function of absolute risk reduction, resulted in a number-needed-to-treat of approximately 7. This mean that reductions of anxiety symptoms could be expected to occur for 1 in every 7 participants of comparable RET.

What Conclusions Can We Take From This Research?
It can be clearly included that RET can help to reduce the symptoms of anxiety. The results found are in line with the more commonly accepted benefits of AET on anxiety and other mental health symptoms and conditions.

The effects of the prescribed AET programs did not vary significantly based on differing participant characteristics, specifics of the exercises given. This provides support for real-world use of various RET programs to serve as a treatment and management method for anxiety symptoms among otherwise healthy adults and chronically ill adults.

Practical Advice
From the findings of the analysis, it seems that while effective, RET may be hard to facilitate due to specific equipment needed for such exercises. This can be avoided however with the prescription of body weight exercises such as squats, lunges, push-ups, and abdominal crunches etc.

Also, with the level of effect prevalence being approximately, 1 in 7, RET may serve best as a compliment to other means of treatment for anxiety, whether that be more traditional pharmaceutical treatment, among other methods.

Further Information/Resources

 * Beyond Blue national help lines and websites
 * Anxiety self-checklist
 * Full Article (see reference 1.)