Poor sleep quality may lower physical activity in people with post-traumatic stress disorder, according to a recent study.

Researchers found that PTSD was independently associated with worse sleep quality at baseline, and participants with current PTSD at baseline had lower physical activity one year later.

Further analysis found that sleep quality completely mediated the relationship between baseline PTSD status and physical activity at the one-year follow-up, suggesting that the association of reduced sleep quality with reduced physical activity could comprise a behavioral link to negative health outcomes such as obesity.

"We found that sleep quality was more strongly associated with physical activity one year later than was having a diagnosis of PTSD," Lisa Talbot, lead author of the study and postdoctoral fellow at the San Francisco VA Medical Center and the University of California- San Francisco, said in a statement. "The longitudinal aspect of this study suggests that sleep may influence physical activity."

For the study, researchers collected and analyzed data from the Mind Your Heart Study, a prospective cohort study of 736 outpatients recruited from two Department of Veterans Affairs (VA) medical centers. PTSD was assessed with the Clinician-Administered PTSD Scale (CAPS). At baseline participants rated their sleep quality overall during the last month, and at baseline and again one year later they reported how physically active they have been during the last month. Of the 736 military veteran participants, 258 had current or subsyndromal PTSD.

Researchers said the results suggest that behavioral interventions to increase physical activity should include an assessment for sleep disturbance.

"The findings also tentatively raise the possibility that sleep problems could affect individuals' willingness or ability to implement physical activity behavioral interventions," Talbout said. "Sleep improvements might encourage exercise participation."

The findings were recently published in the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.