Abstract 3433: The Effects of an 8-week Aerobic Exercise Intervention on Cardiovascular Function and Physical Performance in Sub-Acute Stroke - A Preliminary Study

Abstract

Purpose/Hypothesis: Impaired vascular function and decline in cardiorespiratory (CR) fitness can result in considerable limitations in physical function in people post-stroke. These cardiovascular changes may result from reductions in oxidative capacity, blood flow, and altered muscle fiber type expression in the hemiparetic limb. CR fitness is significantly lower in people with stroke and limits walking speed, endurance and performance of daily activities. Aerobic exercise training is an excellent intervention to improve cardiovascular outcomes in people with stroke. The purpose of this preliminary study was to examine the effects of an 8-week total body recumbent stepper(TBRS) aerobic exercise intervention on vascular function using flow-mediated dilation(FMD), CR fitness, and the 6-minute walk test(6-MWT) during sub-acute stroke. Subjects: We have enrolled 8 participants and 5 have completed the exercise intervention. These 5 individuals (male, n = 3) were 63.0±6.3 years of age; 65.0±45.2 days post-stroke (range: 10-123) and had a total Fugl-Meyer score of 107±22.6. Methods: The exercise intervention consisted of aerobic exercise using the TBRS 3 times/week for 8 weeks. Using the results from the exercise test, target HR range was calculated at 50-59% of HR reserve for the first 4 weeks and then increased to 60-69% of HR reserve for the final 4 weeks. Brachial artery diameter and reactive hyperemia using FMD were assessed in bilateral upper extremities. The vessel was scanned using Doppler ultrasound with a 7.5 Mhz linear array transducer. A pneumatic cuff was placed around the forearm and inflated to suprastolic pressure for 5 minutes. After cuff deflation, images were recorded to the computer for off-line analysis using an automated edge-detection and wall-tracking software. CR fitness was assessed using a metabolic cart during an incremental peak exercise test. To assess physical performance, participants completed a 6-MWT. All outcome measures were assessed at baseline and post-intervention. Results: Preliminary results demonstrated improvements in vascular function, CR fitness and the 6-MWT. Although brachial artery diameter was smaller in the stroke-affected side (3.63±0.52 vs 4.04±0.66), both sides increased in diameter (stroke affected: 3.68±0.44; non-affected: 4.37±0.55) and FMD increased by 7.2% (stroke affected) and 8.6% in non-affected side after the intervention. CR fitness increased by 10%(baseline:15.6±2.8 to 17.2±4.6 ml*kg -1 *min -1 ). The 6-MWT increased from 281±144.1 to 314.3±160.4 (12%) meters. Conclusion: Aerobic exercise in sub-acute stroke appears to be beneficial for improving cardiovascular function and physical performance. Aerobic exercise interventions should be considered an integral component of stroke rehabilitation.