Oxygen Uptake Efficiency Slope Across the Disability Spectrum in Persons with Multiple Sclerosis
Objectives: (i) Examine differences in the OUES between persons with MS and controls matched on sex, age, height and weight; (ii) examine differences in the OUES across the MS disability spectrum; and (iii) examine the relationship between the OUES and other CPET variables.
Methods: 62 participants with MS (EDSS = 1.5–6.5) and 21 non-MS controls matched on age, sex, height and weight completed a symptom-limited CPET using a recumbent stepper and an open-circuit spirometry system.
Results: The OUES was significantly lower in persons with MS (mean=1708.5 (SD=503.7)) compared to non-MS controls (mean=2074.2 (SD=823.2)). A significant, negative correlation was found between OUES and disability (EDSS) (r=-.45). Among those with MS, OUES was significantly correlated with VO2peak, WRpeak, HRpeak and VEpeak (p<.05) and submaximal OUES (i.e., 50% and 75%) was significantly correlated with VO2peak, WRpeak, HRpeak and VEpeak (p<.05).
Conclusions: Overall, the OUES was lower in individuals with MS compared to controls, and decreased as a function of increasing disability level in persons with MS. There was a strong relationship observed between the OUES and other CPET variables in persons with MS. Since the OUES can be determined from submaximal exercise, it represents a promising alternative for expressing CRF in persons with MS.