Inflammation and physical activity in multiple sclerosis patients. A systematic review and meta-analysis

Objectives: Due to the inflammatory nature of multiple sclerosis (MS), the most widely used therapeutic approach targets the immune response but can comprise side effects (e.g. secondary immunosuppression). For these reasons, among non-pharmaceutical interventions without known side effects, physical activity (PA) gained importance because it is feasible, safe and a supportive complementary treatment strategy to alleviate symptoms in MS subjects. Consequently, the main aim of this systematic review is to analyze the effect of PA protocols, as a complementary therapy, on inflammatory status in MS patients. Methods: Four electronic databases (PubMed, Embase, CINAHL, and Cochrane CENTRAL) were systematically searched up to 01 June 2023 (Prospero Protocol ID=CRD42021244418). The refined search strategy was based on three concepts: "MULTIPLE SCLEROSIS" AND "PHYSICAL ACTIVITY" AND "INFLAMMATION". Results: three main findings emerged: 1) untrained subjects showed a negative modulation of inflammatory biomarkers concentrations when compared to trained people (-0.74, 95 %C.I.-1.16, -0.32); 2) training modulated positively inflammatory biomarkers (+0.47, 95 %C.I. 0.24,0.71); 3) Aerobic PA protocol enhance higher positive influence on inflammation. Conclusions: Persistent, low-grade inflammation in MS could be upregulated by non-pharmacological complementary therapies, in particular by regular aerobic PA that could reduce and positively modulate inflammation.