UBC Theses and Dissertations
Cardiovascular disease risk and central and peripheral responses to exercise in individuals with spinal cord injury Zbogar, Dominik
Introduction: Persons with spinal cord injury (SCI) are often physically inactive and as such are at increased risk of cardiovascular morbidity. Fortunately, exercise training in SCI can provide improve health-related physical fitness and alleviate medical complications associated with deconditioning. To optimize health-related fitness gains of exercise in SCI and maximize the potential for chronic disease prevention it is necessary to understand the acute responses (central and peripheral) to exercise. Purposes: The primary purposes of this research were to: 1) determine the contribution of central/peripheral limitations to exercise capacity and 2) examine vascular health in SCI. Methods: Seven persons with paraplegia and seven able-bodied (AB) individuals participated in two testing days. Testing day one consisted of incremental arm crank ergometry to exhaustion with measures of cardiac output, muscle oxygenation, and expired gas and ventilatory parameters. Testing day two involved the measurement of arterial compliance and endothelial function. Results: There was a significant difference for small artery compliance between SCI and AB(6.9±3.7 versus 10.5±1.7ml mmHg⁻¹x100, p< 0.05). Arm total haemoglobin increased significantly throughout exercise. Arm oxygenation decreased until 60% of maximal wattage after which values did not change. Though non-significant, the large effect size (eta²=.142) suggests a trend for higher aerobic power in AB (28.6±5.7mL.kg⁻¹min-1)than in SCI (23.7±2.77mL.kg⁻¹min⁻¹)due to a trend for higher cardiac output values in AB (18.0±5.7L.min⁻¹)than SCI (15.8±3.4L.min⁻¹)at maximal exercise. Conclusions: Small artery compliance is lower in SCI than AB. Leveling off of deoxygenated haemoglobin with total haemoglobin increasing throughout exercise suggests a peripheral limitation to arm ergometry in both groups. A trend for higher cardiac output in AB suggests a central limitation in SCI.
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