HIIT Training Could Offer Greater Exercise Improvements During Stroke Rehabilitation

Ada Tang, PhD
Credit: McMaster University

Longer, grueling bouts of physical activity following a stroke were less effective than short, intense bursts of exercise for improving aerobic fitness among these patients, according to a new study.

A secondary outcomes analysis of a randomized controlled trial comparing short-interval high-intensity interval training (HIIT) against moderate-intensity continuous training (MICT) over 12 weeks, results indicated those randomized to short-interval HIIT experienced greater gains in peak VO2.¹

“This is the first randomized trial to examine a time-efficient, high intensity interval training program to incorporate a phased and progressive approach,” said senior investigator Ada Tang, PhD a physiotherapist, professor and assistant dean of Rehabilitation Science at McMaster University.² “We also used an adaptive recumbent stepper, which we believe allowed more people to participate in high-intensity interval training, even those who cannot walk fast enough or long enough on a treadmill.”

The current study led by Tang and colleagues is an analysis of secondary outcomes from a larger trial. The primary outcome of the overall trial was neuroplasticity and, in the current study, Tang and colleagues offer insight into the effects on secondary outcomes of the trial.^1,2

Per trial protocol, participants exercised 3 times per week for 12 weeks at the Jewish Rehabilitation Hospital or McMaster University in exercise laboratories. Those randomized to HIIT protocol took part in 10x1-minute intervals of high-intensity exercise, interspersed with 9x1-minute low-intensity intervals, for 19 minutes. Of note, the high-intensity intervals targeted 80% heart rate reserve (HRR) and progressed by 10% every 4 weeks up to 100% HRR. Those randomized to the MICT protocol took part in targeted 40% HRR for 20 minutes and progressed by 10% HRR and 5 minutes every 4 weeks, up to 60% HRR for 30 minutes.¹

For inclusion, patients needed to be between 40 and 80 years old, be 6 to 60 months removed from a first-ever stroke confirmed by imaging, and be able to walk independently for at least 10 meters. Exclusion critics included having a score of 2 or greater on the modified Rankin Scale, any contraindications for exercise testing, and having other neurological or musculoskeletal comorbidities.¹

A total of 305 patients were screened and 82 were considered eligible for randomization. The study cohort had a mean age of 64.9 (SD, 9.3) years, 39% were female, and the mean time poststroke was 1.8 (SD, 1.2) years. Among the 82 participants, 42 were randomized to HIIT and 40 to MICT, with no significant differences in baseline characteristics between groups. Investigators pointed out study participants attended 82% of all study visits and no adverse events occurred during the study period.¹

Upon analysis, investigates identified a significant group study time point interaction (χ2=8.46; P = .015) for peak V̇O2 at 12 weeks (mean difference, 1.81; 95% CI, 0.58 to 3.04; P = .004), with the HIIT group experiencing greater gains in peak V̇O2 (Δ3.52 mL/kg/min; 95% CI, 2.47 to 4.57; P <.001) relative to the MICT group (Δ1.71 mL/kg/min; 95% CI, 0.55 to 2.86; P = .001). Further analysis revealed no between-group differences (mean difference, 1.08; 95% CI, −0.26 to 2.42; P = .11) at the 8-week follow-up nor were there any observed group study time point interactions found cardiovascular risk factors or mobility outcomes.¹

“This study shows that people with stroke can also benefit from high-intensity interval training,” said Kevin Moncion, PhD, a physiotherapist who led this study as part of his doctoral studies at McMaster University in Hamilton, Ontario, Canada.² “With the right support and guidance, stroke survivors can safely and effectively engage in high-intensity interval training, significantly improving their overall health and recovery.”

References:

1. Moncion K, Rodrigues L, De Las Heras B, et al. Cardiorespiratory Fitness Benefits of High-Intensity Interval Training After Stroke: A Randomized Controlled Trial. Stroke. Published online August 7, 2024. doi:10.1161/STROKEAHA.124.046564
2. American Heart Association. Short, intense bursts of exercise more effective after stroke than steady, moderate exercise. American Heart Association. August 8, 2024. Accessed August 15, 2024. https://newsroom.heart.org/news/short-intense-bursts-of-exercise-more-effective-after-stroke-than-steady-moderate-exercise.