Cytokine Levels Post Acute Exercise In Individuals With Major Depressive Disorder

Abstract

Individuals with Major Depressive Disorder (MDD), particularly those with more severe depression, often suffer from chronic inflammation. After high-intensity exercise, cytokine concentrations increase in the blood-stream, though moderate intensity exercise results in limited cytokine changes in healthy adults. As inflammation appears dysregulated as MDD severity increases, the extent and magnitude of the inflammatory response to moderate exercise may be augmented by MDD severity, though this is largely untested. PURPOSE: To evaluate cytokine levels during and for up to 50-minutes after moderate exercise in adults with MDD and evaluate the effect of depression severity on cytokine changes. METHODS: Adults (n = 15) with MDD completed a demographic survey and the Patient Health Questionnaire-9 before completing a 30-minute moderate exercise session (Borg’s rating of perceived exertion = 13) on a stationary bike. Blood samples were collected before, mid, immediately after, 25-, and 50-minutes post-exercise. Serum was allowed to clot before being centrifuged, aliquoted, and frozen until cytokine quantification (IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, GM-CSF, IFNgamma, and TNF-alpha) via MILLIPLEX® MAP kit. Low/high depression severity was determined based on PHQ-9 (low: 0-9; high: ≥10). A 2 severity (low/high) by 5 time (pre, mid, post, 25-, and 50-minute post) repeated measures ANOVA was conducted to evaluate cytokine changes across time and by severity group. RESULTS: There was a significant effect of depression severity on IFNgamma [F(1, 65) = 9.26, p < .003)], IL-10 [F(1, 65) = 8.95, p < .003)], IL-12p70 [F (1, 65) = 12.77, p < .001], IL-1beta [F(1, 65) = 6.51, p < .01], IL-2 [F (1, 65) = 13.67, p < .001], and IL-7 [F(1, 65) = 19.63, p < .001], while there were no significant main effects of time or severity by time interactions. CONCLUSIONS: While confirming a depression severity-inflammation link, these findings show a lack of support for an acute inflammatory response to moderate exercise indicating a normal response to moderate exercise in these adults with MDD regardless of depression severity. Along with past research showing the antidepressant effects of moderate exercise in MDD our findings support the use of moderate exercise for symptom management or treatment of MDD.