Physical activity is associated with fatigue in persons newly diagnosed with multiple sclerosis

Fatigue is prevalent, debilitating, and poorly managed in multiple sclerosis (MS), particularly in the early stages. To date, the association between physical activity (PA) and fatigue has not been examined in persons newly diagnosed with MS (PNDwMS), yet this could inform fatigue management in early MS.

This study consists of a secondary data analysis that examined the association between PA and sedentary time and fatigue in PNDwMS.

Participants diagnosed with MS for less than two years (n = 47) wore a waist-worn ActiGraph GT3X+ accelerometer for 7 days to measure time spent (minutes/day) in moderate-to-vigorous PA (MVPA), light PA (LPA), sedentary time (ST), and steps/day. Participants further completed the Fatigue Severity Scale (FSS). We examined the relationships between PA outcomes and FSS scores using bivariate correlations. We performed stepwise multiple linear regression analysis of FSS scores on PA outcomes, controlling for disability status assessed by the Patient Determined Disease Steps (PDDS).

Bivariate analyses demonstrated significant correlations between LPA (r = -0.42), ST (r = 0.33), and steps/day (r = -0.35) with FSS. The regression analysis indicated that LPA was associated with FSS (β = -0.42, R² = 0.18) when LPA, ST, and steps/day were entered into the model. After controlling PDDS (R² = 0.35), the association between LPA and FSS scores was slightly attenuated, but still statistically significant (β = -0.34). Other PA outcomes (i.e., ST and steps/day) were not significantly associated with FSS.

Our results indicated that LPA was significantly and negatively associated with fatigue, even after controlling for PDDS. The finding highlights the opportunity for developing behavioral interventions targeting LPA for managing fatigue among PNDwMS.