Heavy reliance on carbohydrate across a wide range of exercise intensities during voluntary arm ergometry in persons with paraplegia.
OBJECTIVE
To describe and compare substrate oxidation and partitioning during voluntary arm ergometry in individuals with paraplegia and non-disabled individuals over a wide range of exercise intensities.


METHODS
Cross-sectional study.


METHODS
Clinical research facility.


METHODS
Ten apparently healthy, sedentary men with paraplegia and seven healthy, non-disabled subjects.


METHODS
Rest and continuous progressive voluntary arm ergometry between 30 and 80% of peak aerobic capacity (VO2peak).


METHODS
Total energy expenditure and whole body rates of fat and carbohydrate oxidation.


RESULTS
A maximal whole body fat oxidation (WBFO) rate of 0.13 ± 0.07 g/minute was reached at 41 ± 9% VO2peak for subjects with paraplegia, although carbohydrate became the predominant fuel source during exercise exceeding an intensity of 30-40% VO2peak. Both the maximal WBFO rate (0.06 ± 0.04 g/minute) and the intensity at which it occurred (13 ± 3% VO2peak) were significantly lower for the non-disabled subjects than those with paraplegia.


CONCLUSIONS
Sedentary individuals with paraplegia are more capable of oxidizing fat during voluntary arm ergometry than non-disabled individuals perhaps due to local adaptations of upper body skeletal muscle used for daily locomotion. However, carbohydrate is the predominant fuel source oxidized across a wide range of intensities during voluntary arm ergometry in those with paraplegia, while WBFO is limited and maximally achieved at low exercise intensities compared to that achieved by able-bodied individuals during leg ergometry. These findings may partially explain the diminished rates of fat loss imposed by acute bouts of physical activity in those with paraplegia.
University of Miami, Miami, FL, USA. k.jacobs@miami.edu
Kevin A
KA
Jacobs
Patricia
P
Burns
Jochen
J
Kressler
Mark S
MS
Nash
D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D050260:Carbohydrate Metabolism / Q000502:physiology*; D003430:Cross-Sectional Studies; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D010264:Paraplegia / Q000378:metabolism* / Q000503:physiopathology*; D005082:Physical Exertion / Q000502:physiology; D057185:Sedentary Behavior; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000503:physiopathology; D055815:Young Adult
D005230:Fatty Acids, Nonesterified