Sedentary Behavior in People with MS: Impact on Cognitive Functioning

Background: The ubiquitous act of sitting, known as sedentary behavior, has been linked to several illnesses including cardiovascular disease, obesity, type 2 diabetes, depression, and even all-cause mortality. Notably, these associations are independent of moderate-to-vigorous physical activity, which suggests that exercise may not be able to counteract the detrimental effects of prolonged sitting. People with MS (PwMS) are vulnerable to both physical and cognitive impairments as a result of the disease. Notably, deficits in information processing speed have been shown to underlie the higher-level cognitive impairments observed in this population.

Objectives:  The current study examined the relationship between sedentary time and measures of cognitive functioning in PwMS. 

Methods:  Forty-four individuals with relapsing-remitting multiple sclerosis were recruited for the study. All participants provided accelerometry data for a period of 7 days, which was then used to quantify sedentary behavior. Additionally, participants were administered a detailed neuropsychological assessment battery, measuring cognitive domains of working memory and processing speed. 

Results:  Our results show that sedentary behavior predicts over 10% of the variance in processing speed, suggesting that greater time spent sitting is related to slower processing of information in PwMS. Interestingly, these results were significant after removing variance associated with age, disease severity, and time spent in moderate-to-vigorous physical activity.

Conclusions:  This research provides preliminary evidence for the importance of sedentary behavior in understanding information processing, and proposes its potential as a target for intervention trials in MS.