Physical Activity and Sedentary Behaviour In People With Myasthenia Gravis: A Cross-Sectional Study

Abstract Background Despite improvements in the medical management of myasthenia gravis (MG) in recent years, patients continue to report poor health and wellbeing outcomes such as high levels of fatigue, reduced quality of life, walking limitation and reduced balance confidence. Physical activity has been shown to be associated with these outcomes in other populations, however there has been limited research in adults with MG. The primary aim of this study was to describe physical activity and sedentary behaviour in adults with MG and the secondary aim was to explore associations between these behaviours and fatigue, quality of life, balance confidence and walking limitation. Methods A self-report online survey was used to assess physical activity, sedentary behaviour, fatigue, quality of life, balance confidence and walking limitation in 85 community-dwelling adults with MG. Multiple linear regression was used to examine associations between these variables and descriptive statistics were used to analyse participant characteristics, physical activity and sedentary behaviour. Results Most participants (n=53, 62.4%) reported sufficient physical activity to meet public health guidelines, however participants also reported an average of 9 h/day of sedentary behaviour (mean 8.9±3.5). Physical activity and fatigue (R2=0.196), quality of life (R2=0.330), walking limitation (R2=0.305) and balance confidence (R2=0.304) were significantly (p<0.05) and positively correlated, with no associations found for sedentary behaviour. When patterns of physical activity and sedentary behaviour were combined, greater fatigue (R2=0.213), lower quality of life (R2=0.364), increased walking limitation (R2=0.341) and lower balance confidence (R2=0.279) was observed in patients who had greater physical activity levels and lower sedentary time. Conclusions Physical activity and sedentary behaviour is associated with favorable health and wellbeing outcomes in adults with MG. Findings highlight that physical activity and sedentary behaviour may be possible intervention targets, however longitudinal and intervention studies are needed to determine causality.