Preliminary safety analysis of high-intensity interval training (HIIT) in persons with chronic stroke
Daniel L Carl1, Pierce Boyne1,2, Bradley Rockwell1
1a Department of Rehabilitation Sciences, College of Allied Health Sciences, 3202 Eden Avenue, University of Cincinnati, Cincinnati, OH 45220-0394, USA.
Insights
High-intensity interval training (HIIT) is safe for individuals post-stroke, as assessed by electrocardiograms (ECG) and blood pressure (BP). This exercise approach safely elevates heart rates (HR) significantly, offering a potent option for rehabilitation.
Area of Science:
- Cardiovascular Physiology
- Neurological Rehabilitation
- Exercise Science
Background:
- Stroke survivors often experience reduced physical capacity and cardiovascular fitness.
- High-intensity interval training (HIIT) shows promise for improving fitness but requires safety assessment in clinical populations.
- Previous research on HIIT safety in stroke populations is limited, necessitating specific investigation.
Purpose of the Study:
- To evaluate the safety and physiological responses of three distinct high-intensity interval training (HIIT) protocols in individuals with chronic stroke.
- To assess cardiovascular (ECG, BP, HR) and orthopedic responses during and after HIIT.
- To compare the safety and efficacy of different HIIT rest interval durations.
Main Methods:
- Eighteen participants (mean age 61.9 years, 5.8 years post-stroke) underwent screening with a symptom-limited graded exercise test (GXT) including ECG.
- Participants completed three randomized HIIT protocols: 30s work/30s rest (P30), 30s work/60s rest (P60), and 30s work/120s rest (P120), each lasting 20 minutes.
- Continuous ECG, blood pressure (BP), heart rate (HR), and monitoring for cardiovascular intolerance and orthopedic issues were performed.
Main Results:
- No participants experienced adverse events requiring early termination, including arrhythmias, ST changes, or orthopedic concerns.
- HIIT protocols elicited heart rates exceeding 88% of peak HR from the GXT.
- Protocols P30 and P60 resulted in significantly higher peak blood pressure and heart rate compared to P120.
Conclusions:
- Pre-screened individuals with chronic stroke can safely participate in HIIT protocols.
- HIIT effectively elevates heart rate in stroke survivors, potentially exceeding levels seen in moderate-intensity training.
- These findings support HIIT as a viable and safe exercise modality for improving cardiovascular fitness in stroke rehabilitation.
Abstract:
The purpose of this study was to assess safety via electrocardiographic (ECG), blood pressure (BP), heart rate (HR), and orthopedic responses to 3 different high-intensity interval training (HIIT) protocols in persons with stroke. Eighteen participants (10 male; 61.9 + 8.3 years of age; 5.8 + 4.2 years poststroke) completed a symptom-limited graded exercise test (GXT) with ECG monitoring to screen for eligibility and determine HR peak. The 3 HIIT protocols involved repeated 30 s bursts of treadmill walking at maximum speed alternated with rest periods of 30 s (P30), 1 min (P60), or 2 min (P120). Sessions were performed in random order and included 5 min warm up, 20 min HIIT, and 5 min cool down. Variables measured included ECG activity, BP, HR, signs and symptoms of cardiovascular intolerance, and orthopedic concerns. Generalized linear mixed models and Tukey-Kramer adjustment were used to compare protocols using p < 0.05. No signs or symptoms of cardiovascular intolerance, significant arrhythmias, ST segment changes, or orthopedic responses resulted in early termination of any HIIT session. HIIT elicited HRs in excess of 88% of measured HRpeak including 6 (P30), 8 (P60), and 2 (P120) participants eliciting a HR response above their GXT HRpeak. Both maximum BP and HR were significantly higher in P30 and P60 relative to P120. Preliminary data indicate that persons with chronic stroke who have been prescreened with an ECG stress test, a symptom-limited GXT, and a harness for fall protection may safely participate in HIIT, generating substantially higher HRs than what is seen in traditional moderate intensity training.
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