WEDNESDAY, Aug. 6 (HealthDay News) -- Although there is an association between regular exercise and reduced symptoms of anxiety and depression, exercise is not a causal factor, according to study findings published in the August issue of the Archives of General Psychiatry.
Marleen H.M. De Moor, and colleagues at VU University Amsterdam in the Netherlands, conducted a study of 5,952 twins, 1,357 additional siblings and 1,249 parents, all aged 18 to 50 years, who were surveyed on their leisure-time exercise habits and symptoms of anxiety and depression.
The association between exercise and reduced symptoms of anxiety and depression were small and likely caused by common genetic factors, the researchers report. Among identical twins, those who exercised more than their twin had similar anxiety and depression symptoms, and increased exercise did not result in decreased anxiety and depression, the investigators found. The outcome of the study contradicts findings from randomized controlled trials in which symptoms of anxiety and depression are alleviated by regular exercise, the authors write.
"To understand the different outcomes of both types of study, it is crucial to make a distinction between the effects of prescribed and externally monitored exercise in selected subgroups and the effects of voluntary leisure-time exercise at the population level," the authors explain. "Only voluntary leisure-time exercise is influenced by genetic factors, whereas the other type of exercise is environment driven."
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