Inflammatory markers and negative mood symptoms following exercise withdrawal

Abstract

Objective: Physical inactivity is associated with elevated inflammatory markers, but little is known about the time trajectories of reduced physical activity and inflammatory markers. Changes in inflammatory markers in response to withholding regular aerobic exercise were prospectively examined and correlated with increased negative mood symptoms and fatigue that accompany exercise withdrawal. Methods: Participants with regular exercise habits ( N = 40, mean age of 31.3 ± 7.5 years, 55% women) were randomized to aerobic exercise withdrawal or to continue regular exercise for 2 weeks. Protocol adherence was documented using ambulatory actigraphy. Inflammatory markers (interleukin-6, C-reactive protein, fibrinogen and soluble intercellular adhesion molecule-1) were assessed at weekly intervals. Negative mood was measured with the Profile of Mood States (POMS) and the Beck Depression Inventory (BDI), and fatigue with the Multidimensional Fatigue Inventory (MFI). Autonomic nervous system activity was examined using heart rate variability-based indices. Results: Changes in inflammatory markers did not differ between exercise withdrawal and control groups (multivariate p interaction = 0.25). Exercise withdrawal resulted in increased negative mood symptoms and fatigue from baseline to day 14 compared to controls ( p ΔPOMS = 0.008, p ΔBDI = 0.002; p ΔMFI = 0.003), but these responses were not associated with changes in inflammatory markers ( p-values >0.10). Inflammatory markers were also not correlated with autonomic nervous system dysregulation ( p-values >0.10). Conclusion: Inflammatory markers were not increased following 2 weeks of exercise withdrawal. Negative mood symptoms and fatigue were not accounted for by changes in inflammatory markers. Compensatory feedback mechanisms may operate among healthy individuals to promote resilience from the effects of reduced exercise.