HIGH-INTENSITY INTERVAL TRAINING AFTER STROKE – A COMPREHENSIVE ANALYSIS OF FITNESS BENEFITS AND PARTICIPANT EXPERIENCES

Over 100 million people worldwide are currently living with the effects of stroke. Aerobic exercise training is a strategy that may decrease the risk of secondary events and reduce the global burden of disability by improving cardiovascular health, cardiorespiratory fitness (V̇O2peak) and mobility after stroke. Exercise intensity is a key component of exercise prescription for promoting V̇O2peak. High-intensity interval training (HIIT) has emerged as a time-efficient alternative to traditional moderate-intensity continuous training (MICT) in stroke rehabilitation. HIIT involves high-intensity exercise intervals that are short (<1 minute, “short-interval HIIT”) or long (>3-5 minutes, “long-interval HIIT”), alternating with brief, low-intensity recovery periods. There is growing interest in implementing HIIT in stroke rehabilitation. Yet, there is a lack of consensus regarding optimal exercise prescription and limited perspectives of people post-stroke who have participated in HIIT programs. This thesis, comprised of three manuscripts, examined the superiority of aerobic exercise interventions for improving cardiovascular health and mobility outcomes and explored the perspectives of individuals post-stroke who have participated in HIIT. We first conducted a systematic review and network meta-analysis of 47 randomized controlled trials (RCT). We discovered that HIIT appears to be the top-ranked intervention for improving V̇O2peak and gait speed compared to lower-intensity exercise in people post-stroke. We then conducted a multi-site RCT that compared 12 weeks of progressive short-interval HIIT to MICT. We found that short-interval HIIT is a time-efficient and effective alternative to MICT for improving V̇O2peak with possible benefits sustained up to 8 weeks post-intervention. Lastly, we explored the perspectives of individuals with lived experience of HIIT and found that HIIT appears well-received, tolerated, and beneficial for stroke recovery. In summary, healthcare and exercise professionals should endorse and implement HIIT in clinical practice and community settings, given the effectiveness and positive participant perceptions of HIIT after stroke.