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Fuel Oxidation during Walking in Persons with Central Nervous System Pathologies
Author(s) -
Ganley Kathleen J,
Herman Richard M,
Willis Wayne T
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a928-b
Subject(s) - medicine , cerebral palsy , central nervous system , carbohydrate , stroke (engine) , physical medicine and rehabilitation , physiology , mechanical engineering , engineering
Persons with central nervous system (CNS) pathologies select low walking velocities, which limit functional ambulation. We’ve shown (Metabol 54:, 2005) that healthy adults adopted a preferred walking speed (PWS) which relied primarily on fat oxidation for energy. Walking faster than PWS resulted in abrupt increases in carbohydrate oxidation. The purpose of this study was to determine if persons with CNS pathologies conform to this same pattern. Eight overnight‐fasted individuals with various CNS pathologies (e.g. stroke, cerebral palsy, spinal cord injury, traumatic brain injury) walked overground at three self‐determined speeds: preferred, slow, and fast. Rates of O 2 consumption and CO 2 production were measured, and net fuel oxidation rates were estimated using indirect calorimetry. Results revealed primary fuel sources of fat at slow and preferred speeds (34.4 ± 4.2 and 46.2 ± 7.0 m/min) and carbohydrate at fast speeds (56.1 m/min ± 10.5); a wide disparity in speeds across subjects (mean CV = 32.1%) despite similar % contributions of fat and carbohydrate (mean CV = 0.4%); low fat oxidation rates at the PWS compared to healthy adults (21.0 ± 9.9 vs 41.3 ± 3.7 cal · kg −1 ·min −1 ). We propose that fuel selection may contribute to the selection of PWS in persons with CNS pathologies, and that limited fat oxidizing capacity prevents a higher, more functional, PWS. Supported by NSF IBN‐0116997