Exercise training is associated with a reduction in anxiety symptoms among sedentary patients with a chronic illness, according to the results of a review and meta-analysis reported in the February 22 issue of the Archives of Internal Medicine.

“Anxiety often remains unrecognized or untreated among patients with a chronic illness,” write Matthew P. Herring, MS, MEd, from the University of Georgia in Athens, and colleagues. “Exercise training may help improve anxiety symptoms among patients. We estimated the population effect size for exercise training effects on anxiety and determined whether selected variables of theoretical or practical importance moderate the effect.”

Using the Physical Activity Guidelines for Americans Scientific Database, the reviewers identified pertinent articles published from January 1995 to August 2007. They also searched Google Scholar, MEDLINE, PsycINFO, PubMed, and Web of Science through December 2008. In total, 40 English-language articles published in scholarly journals met selection criteria. These studies enrolled sedentary adults with a chronic illness, included an anxiety outcome measured at baseline and after exercise training, and randomly assigned participants to either an exercise intervention lasting at least 3 weeks or to a comparison condition lacking exercise.

The selected studies enrolled a total of 2914 patients. Two reviewers independently calculated Hedges d effect sizes and extracted data concerning potential moderator variables. The investigators estimated sampling error and population variance for all analyses using random-effects models. Exercise training was associated with a significant reduction in anxiety symptoms vs no treatment conditions. Mean effect delta was 0.29 (95% confidence interval, 0.23 – 0.36). The largest reductions in anxiety were seen with exercise training programs lasting 12 weeks or less, with use of session durations of at least 30 minutes and an anxiety report time frame greater than the past week.

“Exercise training reduces anxiety symptoms among sedentary patients who have a chronic illness,” the study authors write. “The magnitude of the overall mean effect (Δ = 0.29) is similar to the effect of exercise training on fatigue symptoms among patients (Δ = 0.37) and on cognitive function among older adults ( g = 0.30).”

Limitations of this study include those inherent in a meta-analysis. In addition, approximately one third of included studies did not provide information about adherence.

“The present results provide clinicians with solid evidence to recommend exercise training to patients as a means for reducing anxiety symptoms with minimal risk of adverse events,” the study authors conclude. “Exercise training may be especially useful for patients who prefer nonpharmacologic treatments because such preferences may influence the magnitude of the treatment outcomes. Perhaps most importantly, the results show that anxiety reduction is a favorable, adventitious outcome of exercise interventions that were designed as a primary treatment or adjuvant for medical conditions other than anxiety.”

The study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2010;170:321-331. Abstract