Cardiovascular hemodynamic response to peak exercise in individuals with multiple sclerosis

Multiple sclerosis (MS) is a chronic neurological condition resulting in decreased aerobic capacity (peak VO₂). The hemodynamic responses to peak exercise in MS are unknown. Further, it is unknown if the hemodynamic responses are due to disease or fitness. Therefore, the purpose was to compare hemodynamic response to peak exercise between individuals with and without MS, with similar peak VO₂. Individuals with MS (n = 21) and CON (n = 21) underwent maximal incremental cycle exercise test to assess peak aerobic capacity (peak VO₂). Heart rate, stroke volume, cardiac output, and blood pressure were obtained every other minute of the exercise test. There were no significant group differences in peak VO₂. All hemodynamic variables increased similarly from baseline to peak exercise in both MS and CON. There was a significant group by time interaction for HR in individuals with MS (p < 0.01), accounted for by age, but no group by time interactions in MAP (p = 0.78), SV (p = 0.11), or Q (p = 0.86). Our findings suggest that individuals with and without MS, with similar peak VO₂, have similar hemodynamic responses to peak exercise. Our data suggest that fitness is a key underlying determinants of hemodynamics responses in individuals with MS.