Cardiorespiratory fitness (V̇O) across the adult lifespan in persons with multiple sclerosis and matched healthy controls.

Objectives: Cardiorespiratory fitness (measured as peak oxygen uptake; V̇O) is a well-established health predictor in the general population and in persons with multiple sclerosis (pwMS). We aimed to investigate differences in V̇O between age groups and the prevalence of V̇O impairments across the adult lifespan in pwMS compared to age- and sex-matched healthy controls (HC).

Design: Cross-sectional study.

Methods: Data from 469 pwMS (EDSS range 1.0-7.0), who carried out graded cardiopulmonary exercise testing during their rehabilitation stay at the Valens clinic from 07/2010 to 10/2022, were retrospectively analyzed. Data from 21,063 HC were extracted from previously published studies containing normative reference values.

Results: With advanced age (i.e., across age groups), a continuous deterioration of V̇O was observed in both pwMS and HC. Within all age groups, V̇O was reduced in pwMS compared to HC with deficits ranging from 29 % to 40 % for females (p < .05), and from 30 % to 41 % for males (p < .05). However, no age ∗ group interaction was observed in neither males (p = .626) nor females (p = .557). With V̇O impairments defined as values below the 5th percentile of HC, a high prevalence was observed in pwMS, with values ranging from 48 % to 100 % across age groups.

Conclusions: The present data provide evidence for a parallel deterioration of V̇O in pwMS and matched controls with advancing age, coinciding with a high prevalence of impairments in V̇O already present in young adulthood in pwMS. Understanding the extent of impairments as well as the age trajectories of cardiorespiratory fitness in pwMS is crucial for designing optimal rehabilitative and preventive interventions.