Abstract W MP58: High Intensity Interval Training May Be Superior to Moderate Intensity Continuous Exercise in Chronic Stroke

Abstract

Introduction: Aerobic deconditioning is a major barrier to stroke recovery. Post stroke guidelines recommend moderate intensity continuous exercise (MICE) to improve aerobic fitness and mobility. High-intensity interval training (HIT) has been shown to be more effective than MICE for improving aerobic fitness among healthy adults and persons with heart disease. However, no previous study has compared HIT and MICE among persons with stroke. We hypothesized that HIT would elicit significantly greater improvement in both aerobic fitness and gait function relative to MICE in this population. Methods: Fourteen subjects (mean ± SD age, 58 ± 10 years; years post stroke, 4.3 ± 2.9) were randomized to HIT (n=11) or MICE (n=5); each 25 min, 3x/week for 4 weeks. HIT involved repeated 30 sec bursts of treadmill (TM) gait at maximum tolerated speed (based on gait stability), alternated with 30-60 sec rest periods. MICE involved continuous TM gait at 45-50% heart rate reserve. Outcomes were measured by a blinded rater before and after intervention, including peak oxygen uptake and ventilatory threshold during graded exercise testing, energy cost of gait, 10m walk test (comfortable and fastest speeds) and TM speed (comfortable and fastest). Mixed effects models tested for significant (p<0.05) differences over time within groups and between the groups. Standardized effect sizes were also calculated. Results: In the HIT group, significant improvement was found for all outcomes save peak oxygen uptake. No significant differences were found in the MICE group. Ventilatory threshold and fastest TM speed improved significantly more in HIT compared to MICE and moderate to large effect sizes were found for all outcomes. Conclusion: HIT is a potent intervention for improving aerobic fitness and gait function in chronic stroke that appears to be more effective than MICE. Further study with a larger sample is warranted.