Are simplified indices of exercise tolerance well correlated to vo2peak among patients with multiple sclerosis: a case- control study

Introduction/Background: Measured maximal oxygen uptake (VO2peak) is the gold-standard to assess exercise tolerance functions. However, this measure can be very challenging in patients suffering from multiple sclerosis (MS) because of several limiting factors (e.g., fatigue, pain, unfamiliarity with exercise, lack of mobility...). Various submaximal indices have been studied to assess exercise tolerance functions in healthy subjects and in persons with neurological conditions. However, whether they relate to the gold-standard have been barely studied. Our aim was to explore the relations between simplified exercise indices and VO2peak among patients with MS and healthy controls. Materials and Methods: This case-control study included 39 patients with MS (mean age: 45±10 years; median EDSS 2.5 (range 0-4)) and 30 healthy subjects (HS) (mean age: 44±8 years). Participants performed a stepwise maximal exercise testing on a cycle ergometer. VO2peak, oxygen uptake efficiency slope (OUES) derived from different reference periods of the exercise test. Descriptive statistics, Student’s T-tests, Pearson’s correlation coefficients between VO2peak and simplified indices and Fisher Z-tests were computed. Measured VO2peak was also compared to PeakWR-based estimation of VO2max by the Bland-Altman method. Results: VO2peak and all the simplified indices were significantly lower in the MS group compared to the HC group (p0.70, p