Similar fat and carbohydrate oxidation in response to arm cycling exercise in persons with spinal cord injury versus able-bodied.

ABSTRACT

CONTEXT Persons with spinal cord injury (SCI) present with low fat oxidation that is associated with poor cardiometabolic health. This study compared changes in fat and carbohydrate (CHO) oxidation during moderate intensity continuous exercise in persons with SCI and able-bodied adults (AB). DESIGN: Repeated measures, within-subjects study. SETTING: University laboratory in San Diego, CA. PARTICIPANTS: Nine men and women with SCI (age and time since injury = 32 ± 11 yr and 7 ± 6 yr) and 10 AB adults (age = 25 ± 8 yr). INTERVENTIONS: To assess peak oxygen uptake (VO2peak) and peak power output (PPO), participants performed progressive arm ergometry to volitional exhaustion. Subsequently, they completed 25 min of continuous exercise at 45%PPO. OUTCOME MEASURES: Respiratory exchange ratio (RER), fat and CHO oxidation, and blood lactate concentration (BLa) were assessed. RESULTS: Data showed a similar RER (P = 0.98) during exercise in SCI (0.97 ± 0.04) versus AB (0.97 ± 0.03) reflecting high CHO use and no differences in BLa (3.5 ± 1.1 and 3.0 ± 0.9 vs. mM, P = 0.56) or fat and CHO oxidation between groups (P > 0.05). However, participants with SCI exercised at a higher relative intensity (P < 0.01, 84 ± 7 vs. 75 ± 7%HRpeak) versus AB. CONCLUSION: Data confirm high reliance on CHO during arm ergometry in persons with SCI. To better compare substrate utilization to AB adults, we recommend that exercise be prescribed according to peak heart rate due to differences in cardiorespiratory fitness between groups.