Background: Anxiety often remains unrecognized or
untreated among patients with a chronic illness. 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.
Methods: Articles published from January 1995 to August
2007 were located using the Physical Activity Guidelines
for Americans Scientific Database, supplemented by
additional searches through December 2008 of the following
databases: Google Scholar, MEDLINE, PsycINFO,
PubMed, andWeb of Science. Forty English-language articles
in scholarly journals involving sedentary adults with
a chronic illness were selected. They included both an
anxiety outcome measured at baseline and after exercise
training and random assignment to either an exercise
intervention of 3 or more weeks or a comparison condition
that lacked exercise. Two co-authors independently
calculated the Hedges d effect sizes from studies of 2914
patients and extracted information regarding potential
moderator variables. Random effects models were used
to estimate sampling error and population variance for
all analyses.
Results: Compared with no treatment conditions,
exercise training significantly reduced anxiety symptoms
by a mean effect of 0.29 (95% confidence interval,
0.23-0.36). Exercise training programs lasting no
more than 12 weeks, using session durations of at least
30 minutes, and an anxiety report time frame greater
than the past week resulted in the largest anxiety
improvements.
Conclusion: Exercise training reduces anxiety symptoms
among sedentary patients who have a chronic illness.