Aerobic Fitness Is Associated with Inhibitory Control in Persons with Multiple Sclerosis

Background: There is a wealth of evidence examining the effects of aerobic fitness on executive control in the general population across the lifespan, but there is markedly less research on this topic in persons with neurological diseases such as multiple sclerosis (MS). Accordingly, it is unknown if the well-established pattern of associations between higher aerobic fitness and better inhibitory control in the general population exists among persons with MS.

Objectives: The current cross-sectional study examined the effects of aerobic fitness on inhibitory control measures, using a modified flanker task, in 28 persons with MS and 28 healthy controls matched by age, sex, body mass index, and education.

Methods: All participants underwent administration of the modified flanker task in a quiet, sound-dampened room, followed by an incremental exercise test to exhaustion on a cycle ergometer with expired gases analyzed using indirect calorimetry for measurement of aerobic fitness as peak oxygen consumption (VO_2peak).

Results: Persons with MS demonstrated lower VO_2peak and slower, less accurate performance on the modified flanker task compared with matched controls. VO_2peak was similarly associated with measures of inhibitory control (i.e., reaction time) in the MS sample and the matched control sample. VO_2peak, but not group (i.e., MS versus control), predicted reaction time on both congruent and incongruent trials of the modified flanker task, irrespective of age, sex, and education.

Conclusions: The current results provide support for the development of aerobic exercise training interventions for improving inhibitory control in persons with MS, much like what has been successfully undertaken in the general population.