Most U.S. adults, even more so those with psychiatric conditions like obsessive-compulsive disorder (OCD), do not engage in the recommended amount of physical activity (PA), despite the wide array of physical and mental health benefits associated with exercise. Therefore, it is essential to identify mechanistic factors that drive long-term exercise engagement so they can be targeted. Using the science of behavior change (SOBC) framework, this study examined potential predictors of long-term exercise engagement as a first step towards identifying modifiable mechanisms, in individuals with OCD, such as PA enjoyment, positive or negative affect, and behavioral activation. Fifty-six low-active patients (mean age = 38.8 ± 13.0, 64% female) with a primary diagnosis of OCD were randomized to either aerobic exercise (AE; n = 28) or health education (HE; n = 28), and completed measures of exercise engagement, PA enjoyment, behavioral activation, and positive and negative affect at baseline, postintervention, and 3-, 6-, and 12-month follow-up. Significant predictors of long-term exercise engagement up to 6-months postintervention were baseline PA (Estimate = 0.29, 95%CI [0.09, 0.49], p = .005) and higher baseline PA enjoyment (Estimate = 1.09, 95%CI [0.30, 1.89], p = .008). Change in PA enjoyment from baseline to postintervention was greater in AE vs. HE, t(44) = -2.06, p = .046, d = -0.61, but endpoint PA enjoyment did not predict follow-up exercise engagement above and beyond baseline PA enjoyment. Other hypothesized potential mechanisms (baseline affect or behavioral activation) did not significantly predict exercise engagement. Results suggest that PA enjoyment may be an important modifiable target mechanism for intervention, even prior to a formal exercise intervention. Next steps aligned with the SOBC framework are discussed, including examining intervention strategies to target PA enjoyment, particularly among individuals with OCD or other psychiatric conditions, who may benefit most from long-term exercise engagement's effects on physical and mental health.
Trial registration: ClinicalTrials.gov NCT01242735.
Keywords: exercise; exercise adherence; obsessive-compulsive disorder; physical activity; physical activity enjoyment.
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